Opposing acceleration: The tragedy of resistance in Brazil

Keywords: Accelerationism, Tragedy of resistance, Deleuze, Affects, Brazil, Illiberalism

Purpose: To highlight and reflect on resistance to Brazil's illiberal accelerationist politics.



Design/methodology/approach: Drawing on the case of public universities and the arts in today's Brazil, we point out a tragedy of resistance (when opposing change fuels its acceleration) and explore a strategy of lines of flight and becomings in the perspective of Deleuze and Guattari's perspective on acceleration.

 Findings: Alongside an oppositional and reactive resistance, that is caught in a tragedy of resistance, we explore an alternative strategy that protects a plurality of life forms and forces, and their becoming. This strategy differs from most critiques of accelerationism.

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Originality/value: This strategy of resistance seems more faithful to Deleuze than the accelerationist strategies that claim to be inspired by him. We suggest another reading of the often quoted passage by Deleuze and Guattari. While Deleuze and Guattari favor continuous deterritorializations of the flows of desire; accelerationism reterritorializes these flows towards an undesirable future.

Introduction

What has to be done when imposed changes threaten us, or feel insufferable?1 What has to be done when, to quote Hirschman's triptych (1970), it seems neither possible to be loyal, nor to exit; and our voices are not heard? Much of the literature on organizational change management has focused on issues of resistance to change. [START_REF] Ford | Resistance to Change: The Rest of the Story[END_REF]Pardo del Val & Martinez Fuentes, 2003;[START_REF] Thomas | Reframing resistance to organizational change[END_REF][START_REF] Land | Meltdown[END_REF]. In recent years, an alternative seems to be gaining momentum: what if instead of slowing down change, we were to accelerate it?

Accelerationism is an invitation to speed up, so that the contradictions and destructive forces of the dominant system, will drag it to its destruction, and open a new era.

Since the election of Jair Bolsonaro, who came to power in 2019, Brazil has become an example of what Fareed Zakaria (2013) calls 'illiberal democracy': with a government that indeed was elected, but makes every effort to render checks and balances inoperative. Its politics can be described as accelerationist in the sense that it activates a set of mechanisms and contradictions, to precipitate the current democratic system towards the advent of an order where free market forces, a certain moral order, and a naturalization of inequalities, dominate; and where no divergence is allowed. Opposition is aroused, but in order to be delegitimized and swept aside. Prominent in the resistance, are public universities and the arts (two areas that promote reflexivity, which are especially under attack by the government); but they seem trapped into what can be called a 'tragedy of resistance'. Indeed, to do nothing is to accept change, which seems to spell the end of the arts and humanities in Brazil. But resisting, expressing dissatisfaction and criticizing the government measures, leads to political responses that accelerate destructive outcomes. One cannot resist to resist, but to resist is to accelerate towards unwanted ends.

How then to resist to an accelerationist policy that speeds up towards a change that threatens one's own existence; and how to avoid the trap of a tragedy of resistance? There is probably no one general answer, but we would like to foreground a potential form of resistance, that we have observed in the university and the arts in Brazil.

There have been many reactions, in the form of criticism and frontal opposition, but we have also observed an acceleration in the production of texts and works, that underline the affects and forms of relatedness, different from those advocated by the regime. Instead of accelerating the system towards a desired alternative state, there has been an accelerating of lines of flight and of plural becomings; instead of a unified front line, a molar micropolitics has been created. All of this entails betting on the affects and vital forces safeguarding the minor and the vulnerable. Paradoxically, this reaction seems more Deleuzian than the accelerationisms that claim to be based on Deleuze. We contend that the current accelerationisms are based on a challengeable reading of Deleuze.

Acceleratonism is a very specific perspective on social change with significance for change management. As Nick [START_REF] Land | A quick and Dirty Introduction to Accelerationism[END_REF] makes explicit in his quick and dirty guide it is about removing the negative feedback circuits that keep systems in the same place, preventing them from evolving further. In Land's (2010) view the aim is that change becomes self-feeding and self-directing, and more and more powerful. Or, in other versions (e.g. Williams & Srnicek, 2013 ;[START_REF] Cuboniks | Xenofeminism: A Politics for Alienation[END_REF], accelerationism is meant to bring about a new state of society, free of a of the brakes that prevent radical progress.

Our contribution is to document a form of resistance to change that is very different from its usual forms. Rather than slowing down, it is about speeding up: doing more and better, to make powers deemed destructive derail, to create lines of flight and to maintain and make grow the endangered forces of life and solidarity.

In the remainder of this text, we will identify four versions of accelerationism that share certain mechanisms, but call for very different futures. After a brief description of our engagement and method, we will then present the accelerationist policy of the Brazilian government, resulting in the tragedy of resistance in particular for public universities and the arts. This will be followed by another less common form of resistance. We propose that the latter promotes an acceleration that seems closer to Deleuze and Guattari than the more common accelerationisms. Finally, we characterize our alternative form of resistance, discussing its mode of critique, its non-directive poetics of knowledge, its place of affects and vulnerability; and contrast it to the critics of accelerationism.

Speed up to where? Four directions for accelerationism

That many of our life, social and production rhythms are accelerating seems to be a common experience. This is also one of the well-known theses of Hartmut Rosa (2005), for whom, despite all the technologies designed to save time, experience is of having less and less time. Social pressure on time is proposed to be one of the main sources of contemporary alienation. Modern societies need to always accelerate, simply to maintain the status quo, which leads to crises and self-destruction [START_REF] Rosa | Appropriation, Activation and Acceleration: The Escalatory Logics of Capitalist Modernity and the Crises of Dynamic Stabilization[END_REF]. To resist, or to regain a better life, requires decelerating. Yet for the promoters of accelerationism, change on the contrary is a question of accelerating! Supposedly we must accelerate, in order to precipitate change towards a new social order.

Already in the Communist Manifesto, [START_REF] Marx | Manifesto of the Communist Party[END_REF] identified contradiction as one of the internal conditions of capitalism. What looks like incoherence within the system, and therefore a source of its destruction; may be the principle of its renewal. Crises that feed capital, lead to transformations and guarantee its systemic survival. Acceleration (of production, labor and consumption) is indeed at the core of capitalism, in its quest to increase profits, and how modes of production, and also modes of life, are shaped. Accelerationism proposes to accelerate the contradictions within the system, and to rely on the powers within the system to shift society towards a new order; that is, towards another form of life and of the distribution of wealth and capabilities.

We assert that there is no such thing as accelerationism. Disagreements are huge about what is wrong or no longer works in our current system. Which trends accelerate and what future is desirable? Accelerationists range from (extreme) right to (extreme) left. Let's briefly present what seems to be the four main contemporary accelerationist currents.

Benjamin Noys (2010) adopted a word first coined by Zelazny (1967) in a novel, and proposed the term 'accelerationism'. But it was Nick Land who was the first champion of accelerationism. [START_REF] Land | Meltdown[END_REF] took inspiration from Deleuze and Guattari's analysis of capitalism (1972,1980). According to Land, the real is always stratified and sedimented, which limits life and thought. Freedom comes from destratification and deterritorialization. It is necessary to target points of intensity of the 'machinic', and to accelerate them, in order to free ourselves more and more from practical limits, and from old strata and territories.

Capitalism is a machine for destroying: borders, local markets and sovereignties, old value systems, et cetera. Accelerating means removing everything that hinders the development of power, innovation, and technological possibilities. Accelerationism is about deterritorialization and enhancing the creative (auto-)destruction of capitalism [START_REF] Land | A quick and Dirty Introduction to Accelerationism[END_REF].

But unlike Deleuze and Gattari, Land's aim is not to make other modes of existence possible, rather it is to pursue ever greater intensities, of power, and thus towards (his concept of) freedom. Acceleration, intensity, potency are valued, here, for themselves. Ray Brassier (2010) has argued that this means giving up more and more agency, and embracing the powers of the system; in other words the forces of capitalism. Indeed, Land's version of accelerationism turns out to be a way to speed up the move towards neo-liberalism, where competition and market expansion have fewer and fewer limits. Land's ideas, such as breaking loose from what holds back technologies from inventing the future of humanity, could not but fail to please some of the players in Silicon Valley [START_REF] Turner | On Accelerationism[END_REF].

Accelerationism might, as Land has proposed, provoke a speed-up towards a kind of 'Dark Enlightenment'. Land's accelerationist theses have gained a lot of traction among the neo-reactionary and the alt-right movement. Indeed, somewhat surprisingly for a movement originating in the concepts of Deleuze and Guattari, this second version of accelerationism, explicitly inspired by Nick Land, has been embraced by neo-reactionaries, especially white supremacists. Starting from the idea that governments are corrupt, and that the liberaldemocratic order is a failure; they call not for an extreme neoliberal regime, but for the disrupting of the social order and consensus, in order to accelerate in the direction of an exclusively white-dominated order [START_REF] Beauchamp | Accelerationism: the obscure idea inspiring white supremacist killers around the world: How a techno-capitalist philosophy morphed into a justification for murder[END_REF]. This form of accelerationism was, for instance, explicitly cited as a source of inspiration in the Christchurch Mosque massacre in Australia and by the American neo-Nazi movements (idem).

One can show interest in some of Nick Land's theses, but reject his right-wing drift, embracing instead a pro-social objective. Such a left accelerationism is probably best embodied by the Accelerationist manifesto written by Alex Williams and Nick Srnicek (2013).

The two authors warn that global climate change could lead to the destruction of fresh water and energy, to mass famines, to the collapse of economic systems, to financial crises, to hot and cold wars; making the current norms and organizational structures of politics untenable.

Our political imaginary, and in particular the old recipes of the left, have supposedly become impotent. Rather than "folk politics of localism, direct action, and relentless horizontalism", rather than "habitual tactics of marching, holding signs, and establishing temporary autonomous zones", an accelerationist politics is needed to redirect technological, social and cognitive advances, towards social ends. This accelerationism is out to unleash latent productive forces, accelerate the process of technological evolution, attract flows of capital, construct an intellectual infrastructure, support wide-scale media reform and to control all of this via an ecology of organizations and a pluralism of forces. Resonating positive feedback loops are to lead to a collectively controlled, legitimate, vertical authority. This is proposed to be an effective way for regaining a leftist hegemony, and some sort of collective self-mastery [START_REF] Morgan | Will we work in twenty-first century capitalism? A critique of the fourth industrial revolution literature[END_REF]. This version of accelerationism seems to be more easily accessible to those enjoying a privileged position; i.e. college trained and with (semi-)professional positions.

Another manifesto, which shares some of the references, energy and logic of the previous one, came out two years later, from the Laboria Cuboniks as Xenofeminism A Politics for Alienation (2015). As a renewed version of cyberfeminism, the prefix "xeno" refers to alien, in its dual meaning of radical otherness and of alienation. For the six authors of the manifesto, one has to accept more alienation and more unnaturalness, to achieve more freedom; 'nature' they claim is often taken as the norm to justify limitations, inequality and violence. The emancipatory potential of technology remains controlled by the markets. To accelerate is to break free from limitations. The authors lament that the traditional methods and agendas of feminism have become bound to fixed localities and fragmented insurrections, that are insufficient in our technologized and globalized world. They call for redirecting the resources of technology and media, and for building an adequate intellectual infrastructure for change It needs to be an intersectional infrastructure: Xenofeminism is "gender-abolitionist,"2 in order to "let a hundred sexes bloom!". They also aim at eliminating power asymmetries due to race and class differences. To this aim, the struggle must be conducted at all levels, including in homes, and especially concerning the body. In its horizon, lies "an emancipatory and egalitarian community buttressed by new forms of unselfish solidarity and collective selfmastery".

What all these accelerationisms have in common is the rejection of the most common orms of politics, the pursuit of key intensities to reach a crucial tipping point, a long-term approach based on the assumption of a linear direction of time, and a willingness to make the unlimited use of all available means, including technology, mass media and the construction of a coherent and instrumented system of thought. Mont-Pèlerin is regularly cited as an example of how to build such a new society. The ends justify the means, in approaches that may be authoritarian. However similar the logic, there are deep disagreements about the main objectives of the struggle.

A single case study with participating to meetings and other sources

Our approach is based on the study of a singular case which seems to us particularly significant [START_REF] Yin | Case Study Research[END_REF]. Its limitations are clearly that it is based on a case in a particular period, but the same issues, trials and responses seem likely to be repeated in other contexts and periods [START_REF] Moriceau | Generalizability[END_REF].

The descriptions and reflections developed in this text relied on discussions and the collaboration of four research groups from three public Brazilian universities. Four meetings were held between November 2018 and August 2019, and a nationwide conference was organized dedicated to the theme of human rights, power relations and resistance practices in the context of Brazilian organizations and institutions. The meetings were attended by researchers and students and delt with questions regarding the perception of the participants about the main dilemmas faced by the universities they belong to, as well as questions pointing to resistance tactics. Participants also attended national forums where they come into contact with situations and problems faced by researchers from other Brazilian states. Many were also linked with artists and art organizations. Thus, the narratives constructed in the meetings interweave lived experiences with experiences reported by researchers who belong to this network. This main source of information was triangulated by reading the texts and testimonies available in the media and social networks, and by the multiple exchanges which took place in the academic and artistic circles.

The meetings evidenced the effects of government policy, such as cuts in funding for the social sciences and humanities, accompanied by a delegitimization of their knowledge production; prejudices and stigmatizations related to gender, race and class; pressure exerted by the federal government so that universities dedicate themselves to form technically qualified professionals, in detriment to a critical and philosophical formation. Discussing resistance tactics, the participants emphasized the collective engagement in practices of pedagogical and epistemic experimentation, in order to build more hospitable and welcoming environments for teachers and students. Hospitality is developed in research groups, in classrooms, in interdisciplinary seminars, and in welcoming diverse knowledge and epistemes that express a plurality of ways of life that inhabit public universities. The valorization of experiences, languages, corporeities, and unique vulnerabilities involves everyone in a potential affective and scientific network, allowing the production of knowledge to flourish in an environment marked by biopower and the collective construction of an ethics of care. All emphasized the strength and increase in commitment to this form of collective resistance, that it has to be strengthened, to be accelerated. 3The strategy for interpreting these observations is then as follows: we describe three examples of the types of resistance reported in the meetings using Deleuze's concepts. The accelerationist literature relies extensively on Deleuze's concepts, and these seem well suited to analyze the examples. We then offer another reading of the passage where Deleuze proposes to accelerate. This will allow us to highlight the originality of the case in relation to the literature on accelerationism and on resistance to change.

Accelerationism in Brazil, the tragedy of resistance and lines of flight

Let's turn now to the case of the Brazil as led by Jair Bolosnaro, where many elements of an accelerationist policy can be distinguished, and where resistance inside public universities and the arts seems to be caught in a tragedy, where the opposition fuels the acceleration. We will, then, explore the hints of another form of resistance, oriented towards affect and lines of flight.

Brazil's accelerationist politics

Jair Bolsonaro was elected with the support of powerful economic groups, neo-Pentecostal movements, and without hiding his affinity with certain Nazi or dictatorial practices. The society, towards which he openly declares he wants to lead the country, would be characterized by drastically reduced social, labor and human rights; and would impose ways of life based on specific moral values and be characterized by enhanced inequalities. On the one hand, this looks like a conservative slowing down or a turn backward, in the grand narrative of human progress towards democracy, equality and freedom. But on the other hand, we can distinguish some typical accelerationist mechanisms used to speed up the advent of a different system. Note that if narratives are important in justifying and gaining support for change, acceleration relies on the acknowledgement of certain trends, mechanisms and powers.

On the economic side, with a minister of economy who brags about being a member of the Chicago School of Economics, some of the proposed measures are well known [START_REF] Boadle | Brazil's 'Chicago Oldies' aim to revive Pinochet-era economic playbook[END_REF]. Reduction of labor and social security rights, forcing everyone to "give all the running they can just to keep at the same place" (paraphrasing Lewis Carroll), with the threat of being left behind all alone. Regulations are dismantled as a hindrance to growth; tax cuts for the richest are justified by claiming their exceptional contribution to economic welfare. Reduction of labor and social rights, reframed in the narrative of entrepreneurial opportunity, leading to hordes of vulnerable people roaming the streets, accused of not having done justice to the opportunities they have had, and forcing them to accept ever worsened working conditions.

The largest numbers need to contribute to the economic machine by means of their economic and existential precariousness; privileged classes are to benefit from more advantages and their signs of distinction. In this persiflage of a meritocratic society, always more lives are precarious. Bodies are not all weighed the same; not all deserve to be mourned [START_REF] Butler | Precarious Life: The Powers of Mourning and Violence[END_REF].

All investment is to be directed towards economic efficiency, including intellectual investment. Academic criticism, especially in the social sciences, is considered to be a brake on growth, and wasted effort that we urgently need to do without. Brazilian public universities, the largest producer of scientific knowledge in the country (Web of science group, 2019), are attacked; while international advice and knowledge, dedicated to modes of heightened performativity, are purchased. Knowledge has to be instrumental, or its production is a waste of money, and forms an improper orientation for students. The arts, unless they contribute to what Boltanski and Serroy (2013) call the 'aestheticization of the world', by enhancing competitiveness, are not appreciated.

Addressing the social dimensions of diversity and plurality, is taboo. Strengthening the mythic single body of the nation, conceived of as a hierarchical body capable of assigning each one his specific place, is the goal. Whomever defends the existence and need for a plural society, is treated as an enemy. Women's rights are denied in favor of traditional roles; diversity of and within genders, are made ridiculous or considered with suspicion. In the name of religion, unquestionable norms and an exalted form of machismo is defended. Indigenous rights, especially land rights in Amazonia, are contested or bypassed. Schemes for positive action, in favor of black people are stopped; keeping most in subaltern situations.

One of the main mechanisms to accelerate the advent of the desired society is provocation. Provocation is used to elicit reactions and opposition, in order to identify 'objectionables' to be discredited and destroyed. In case of failure, another provocation is attempted. In parallel, shameless statements of false truths, hate speech and even calls for hate crimes, are disseminated on social networks by supporters of the government, seeking widespread popular support. Critical reaction provides the government with opportunities to attack (yet appearing to only react), hence weakening or eliminating opposition. Demands and contestation are labeled and dismissed as "communist". Opposition is be twisted to accelerate the advent of the desired opposition-less, white, patriarchal and elite order.

The tragedy of the resistance

How can such an accelerationist regime be resisted? We will examine the case of the Brazilian public universities and of the arts. Both have been particularly under attack by the government, because they often promote a critical and pluralistic vision of society, competing with the government in appealing to the minds and bodies of their public(s).

The 109 federal public universities, which are the main centers of knowledge production in Brazil, especially in the social sciences and humanities, have changed their face significantly over the past two decades [START_REF] Peres | Um ano de ataques[END_REF]. More and more professors and students have come from class, ethnic, gender and sexual orientations of minorities. The 2012 quota law accelerated this trend. This has had repercussions on the knowledge taught, on the research topics investigated and the dissemination of ideas. The universities embody and disseminate a plurality of world(views), revealing the complexity of the world in support of the contestation of any single truth, shaking hegemonic cultural models and promoting the emergence of voices and places of speech, hitherto silenced. Public universities are now caught up in the tragedy of the resistance. Acts of opposition are taken as pretexts, or are even provoked, in order to further limit university freedom and accelerate towards the society willed by the government.

Government attacks have been numerous against the dissemination of "gender ideology" and "cultural Marxism". Universities combine two sins: they divert from the construction of a productivist educational ideology focused on the training of professional technocrats, dedicated to the production of tangible goods, with a quick return on capital; and they promote republican and democratic values, by trying to foster critical minds. To give but one example of the tragedy of resistance: the government used the pretext of an academic event, where contemporary policy was discussed, to cut funding to three federal universities by 30%. (Saldaña, 2019a) The government claimed that the universities were underperforming and that the event was creating chaos. However, these three universities ranked among the best. The attack could not be left unanswered. There were protests and petitions, pointing out the unjustifiable nature of such huge budget cuts. The government used the protests as a weapon, to attack what they defined as "ideological opposition," cutting the humanities and social sciences budget for all 109 federal universities by 30%. (Saldaña, 2019b) Again, the universities, and part of civil society, could not let this happen without saying anythingthere were protests again. The government reacted by threatening to cut the total budget of the public universities by 30%. This is just one example of the government's accelerationist strategy. The government provokes opposition, fostering all sorts of opposing actions, in order to go much further in the establishment of its desired policies. It also illustrates the tragedy of resisting accelerationism.

To do nothing, is to allow the government to impose an order that is contrary to democratic values; but on the other hand, to react and protest, and to resist change, leads to the acceleration of one's own destruction.

Quite the same tragedy has taken place in the arts world. Symbolically, but significantly, the Ministry of Culture has been suppressed, its departments being transferred to a branch of the Ministry of Tourism. The arts are now receiving far fewer subsidies, and have been assigned to serve the government's image of the country, as an effort at the aestheticization of the nation. Reactions were quick and courageous; art works and artists' voices protested and denounced, but the government used the opposition as a pretext to denounce the "leftist and degrading drift" of contemporary artistic production, and to go one step further in the controlling of the arts.

Arts have been vibrant in Brazil, embodying minority voices and social criticism. But for a government, anxious to control communication, and claiming to be one with the people, the space for different voices is minimal. "We must return to classical arts to preserve our culture," shout the pro-government marchers, as they close ranks in support of traditional (past) symbols of Brazilian identity. This is a 'culture' that does not produce art, and its art is not really representative of the diversity of Brazilian culture. Amalgamating 'culture' and 'art', is an efficient narrative strategy, making it possible to orchestrate attacks on artists and artistic works that address the political, economic, symbolic, moral and social order, being enforced by the government and its supporters. It echoes the military dictatorship, during which media were controlled and symbolic events were created to mould the image of Brazil as a free, beautiful and happy country: the country of soccer, samba, sweat and beer.

In order to support a creative arts scene and to broaden the audience in popular circles, a large part of the funding was organized by the prior Lula and Rousseff (social-democratic) governments, via calls for subsidies. The proposals had to win the approval of assessors appointed by the public authorities and of the companies that received matching tax reductions. In exchange, the ticket price of performances was kept very low. The calls now include the clause that the proposed work must have no political content. Many theatre companies have had to close their doors, and many actors and technicians have had to take a second job to survive.

An example of protest was seen during the carnival of 2019. Carnival continues to be a moment when society criticizes itself. The time of carnival is a time of the suspension of the symbolic order, and includes an invocation to chaos as narrative inspiration. The samba school Estação Primeira de Mangueira paid homage in its parade to the councilwoman and human rights activist Mariele Franco, who was murdered with 14 shots in the city of Rio de Janeiro; a still unresolved case in which politicians and other prominent personalities seem to be involved. And also homage was paid to Dandara, a transvestite, who was murdered in the city of Fortaleza. The whole ritual of her torture and death was transmitted online by a cell phone camera. With the theme: "Stories to teach big people," the Mangueira samba school told the story of Brazil from the perspective of its popular heroes. It was the most noted march of the year. The carnival commented: "the school sang the story that is not portrayed in textbooks".

But as [START_REF] Schechner | The street is the stage[END_REF] reminds us, after Shrove Tuesday, there is Ash Wednesday; when order returns all the more strongly.

Affective lines of flight

Forms of resistance are diverse, and we would like to highlight one form which appears as a possible way out of the tragedy, of resistance only producing more repression. In accord with what was just written; we could see, and received many testimonies of, a huge increase in the production of academic and artistic work emphasizing affect, relatedness, human and ethical experience, including an openness towards people in vulnerable positions: black people, LGBTQI, the disabled, and the poor. We interpret such attempts, drawing on a Deleuzian vocabulary, as the creating of lines of flight, outside of the accelerationist machine and tragedy; happening in the midst of the mechanisms and machinations of governmental affects of hatred, resentment and widespread competition; and of the propagation of narratives that imprison minds as well as bodies. Facing up to the suffering of the Other, is a way of escaping the grip of the dominant system by rekindling other forms of connection, solidarity and resistance, and creating a 'micropolitics at the molar level'; i.e. at the meso-level of arrangements between individuals and institutions. The government's politics emphasize biopolitical classification, clear-cut categorization, and they promote 'oneness'. Artists and scholars have proposed other percepts, affects, and concepts; namely, assemblages and encounters; narratives and fables; scenes and spaces of speech that offer places, bodily arrangements and possibilities of thought outside of the accelerationist frame. Let's describe a few examples, to make the strategy more graspable.

Exemplary among many possible works, is a participatory research project that entails investigating and presenting traditional knowledge from oppressed communities by the members of those communities. The objective, following Walter Benjamin, is to create alternative descriptions, giving a dignified representation to the nameless and oppressed. In other words, following Didi-Huberman (2016, p.422), the goal is to render sensible and readable "failures, the places and moments by which peoples, in declaring their powerlessness, affirm at the same time what they lack, what exposes them to disappearance and what they desire". Or, in yet another phrasing, to give faces to the anonymous so they can be considered as witnesses and bearers of secrets [START_REF] Rancière | Le Destin des images[END_REF]; this in order to discover new temporalities, opening the narratives to experimentation [START_REF] Rancière | Les bords de la fiction[END_REF]. Such a strategy can, with [START_REF] Deleuze | Difference and repetition[END_REF]Gattari (1972, 1980), be labelled as 'becoming-minor', 'deterritorialization' and a 'creation of new arrangements'.

Such identifiers that also would function in the previous samba school example. The illustrations are most definitely of opposition; relayed by media and via digital networks, transmitting affect, memories, and competing narratives and imaginaries, which are open to multiple alternative arrangements. The references and images are linked with the struggles of indigenous people, blacks, women and others excluded from the government's official history of the country; reversing the hegemony of the heroes of the official storytelling. Both the grand narrative of Brazilian bravura, and the temporality of accelerationism, are hereby to be rivaled by other framings.

A third example is the theatre play E ainda assim se levantar ('And still to stand up'), where three individual trajectories embodying the hurdles and subjective fights at the crossroads of Brazilian conservatism, machismo, competition and narcissism, are portrayed. Naked, wavering, lost bodies, caught up in narratives of protest, bombard the audience with a range of affects, triggering reflexivity about one's own existence, and inviting the spectators to dismantle the clichéd narratives, and re-place them with the history of struggle in Brazil. A play that can be considered as what [START_REF] Deleuze | Difference and repetition[END_REF] calls theater of repetition, where what is played out on stage is imprinted by the forces that run through society, forces that are directly communicated to the audience. It is not a question of narrating or explaining these forces, but of making them experienced for a collective awareness of the arrangements that traverse us.

Accelerationism and Deleuzian politics

Our presentation of the situation in Brazil confronts us with a paradox. While government policy can be seen as corresponding to the first two forms of accelerationism described above, and while accelerationism claims to be inspired by Deleuze; it is ultimately forms of resistance, attempting to escape the accelerationist frames, that resonate most closely with the politics put forward by Deleuze. Before drawing lessons for change we wish to return briefly to the passages where Deleuze and Gattari (1972) proposes to accelerate.

Accelerationist interpretation is indeed based on some of Deleuze's concepts, in particular in regard to pre-individual machines; but ultimately, the interpretation does not sound very Deleuzian. As Deleuze encouraged the creative reading of philosophical texts departing from the letter to produce new thoughts, it is difficult to speak of a misreading; but we would like to propose an alternative reading.

Just a quick note justifying our focussing on Deleuze and Guattari. They are indeed at the centre the inspiration and debates surrounding accelerationism and its links with capitalism, conservatism and territorialisation. Sometimes one discovers very different interpretations of the same passages. In one of Land's (2010) founding texts, Deleuze and Guattari are indeed the only sources quoted, and undoubtedly the text is inspired by their concepts. [START_REF] Land | A quick and Dirty Introduction to Accelerationism[END_REF] argues that accelerationism was "in its entirety" contained in Deleuze and Guattari's their work and that "Deterritorialization is the only thing accelerationism has ever really talked about' (unpaginated). [START_REF] Noys | Malign Velocities: Accelerationism and Capitalism[END_REF] has also attributed a similar inaugural and decisive role in accelerationist thinking to Deleuze and Guattari; as have [START_REF] Mackay | Mackay & Avanessian #Accelerate: The Accelerationist Reader[END_REF] in their accelerationist reader, as well as the commentators [START_REF] Rosales | Deleuze and the Accelerationsists[END_REF] and [START_REF] Henkin | Accelerationism and Acceleration[END_REF] for example.

There is, indeed, a machine-like and accelerationist dimension to Brazilian politics. But it would probably not be this majoritarian movement that Deleuze would propose to accelerate; but rather its cracks, its lines of flight, and the minor creative developments that emerge in its interstices. In Anti-Oedipus, Gilles Deleuze and Félix Guattari (1972) pointed to the omnipresence of machines; machines that just never stop producing, regardless of their ends. These are machines that produce money, forms of life, and desires. The machinic processes pass through our bodies.

Deleuze and Guattari distinguish three forms of society: (i) primitive society in which everything is grounded in the earth, including our bodies; (ii) despotic society, in which everything is meant to refer back to the body of the despot; and (iii) capitalist society, in which everything is grounded in the unstable body of capital. In Brazil, which cultivates nationalist fervor, the three overlap. Called the Messiah by his followers, in the manner of the despotic society, the president's body becomes the divine body: outside of him there is no existence.

Desires are channeled towards the machine of production and the despotic body. Anything that could disperse colonized desire, is avoided and fought against. Everything that is diverse, that allows desire to arise and multiply, is considered to be an attack on the body/god/despot of the ruler. Thus, reflexive art, education, and culture, are enemies of the discursive reterritorializing machine. Bolsonaro's ruling is caught up in machines that bypass and override official institutions. A message on president's twitter is capable of producing more effect than an official speech. Social networks' instantaneity and effects of proximity, reinforce the impression of the nation as one body, producing mobilizing affects and explosions of hatred, against those who could slow down or oppose the accelerationist system.

Most accelerationisms refer to Deleuze and Guattari. Yet, the idea of accelerating is far from being pervasive in Deleuze and Guattari's work. They once proposed that a strategy might be not to withdraw, but to go further, and "to accelerate the process" (Deleuze & Guattari, 1972, p. 285). However, in this often quoted passage, the accelerating strategy was meant to oppose the danger of closure of territorialization; i.e.: "a curious renewal of the fascist economic solution" (ibid.). Moreover, their proposition to accelerate was preceded by a "perhaps": "For perhaps the flows are not yet sufficiently deterritorialized, not sufficiently decoded" (ibid.). For Deleuze and Guattari, territorializations and codes, are what prevent becomings of new forms of life, and the invention of other paths. We are talking here of opening up to global flows, decoding codes that are too strict, and the possibilities of creativity, of ruptures, and of new institutional futures. Capitalism manages deterritorialization and decoding, but each time it reterritorializes, it recodes and rechannels the flows in its own workings. If for Deleuze and Guattari it is a question of accelerating, it is according to us a question of pursuing the possibility of becoming minor; of encountering alternative vital forces and of exploring new flows of desires. This is not to reterritorialize the flows in an accelerationist machine directed towards a desired future; but for the flows of desires to continue to be deterritorialized. This is how we understand their "perhaps the flows are not yet sufficiently deterritorialized".

If it is a question of accelerating, it is not to remove the last remaining brakes on the free play of the capitalist system, or to develop a 'pure' system of white supremacy. Deleuze and Guattari fiercely criticized capitalism, in the name of the most disadvantaged, because it acts as a machine that devours their lives, energies and bodies; and in which they paradoxically invest: "We see the most disadvantaged, the most excluded members of society invest with passion the system that oppresses them, and where they always find an interest in it, since it is here that they search for and measure it" (idem, p. 415). They were in a way anticipating an aspect of Nick Land's accelerationism. Land provokes a certain jouissance, or addictive enjoyment, that loops into a system that wants power for power's sake, becoming affectless and depersonalizing [START_REF] Noys | Malign Velocities: Accelerationism and Capitalism[END_REF]: "Oh, certainly, it is not for himself or his children that the capitalist works, but for the immortality of the system. Aimless violence, joy, pure joy of feeling like a cog in the machine, crossed by flows, cut by schizophrenia" (Deleuze & Guattari, 1972, p.415).

Alex Williams and Nick Srnicek's accelerationism could be seen as a possible war machine, but it is one that runs counter to Deleuze and Guattari's taste for mulitplicities, rizhomes and plateaus. Deleuze and Guattari would probably feel better at home with xenofeminism. Expressions such as "To each his own sex (...) It is always with worlds that we make love," (Deleuze & Guattari, 1972, pp. 352 and 349) challenge the principles of binary difference [START_REF] Ramond | Deleuze : schizophrénie, capitalisme et mondialisation[END_REF]. But there would have been reservations, because of the dangers of systemic closure.

Deleuze never proposed a global, voluntary and targeted action; opposing Antonio Negri on this point (Zurabishvili, 2002). Deleuze and Guattari favored guerrillas and pourparlers; that is, a micropolitics of molar, minor or dissident politics. For them, revolutions take place on the micro level and often are invisible. They are the work of minorities, capable of inventing the new: "a minority has no model, it is a future, a process" (apud Zurabishvili, 2002). Becoming-minor is to escape the territorialization in a set of cades, places, and roles.

The system oppresses and blocks minor emergence, and expressions of pure differences, that are vital creative forces. But the emergent tends to become the majoritarian and to stifle future creation. There is a danger, in channeling becoming that the becoming is no longer allowed to become. In order to break or create cracks in an oppressive and alienating system, the lines of flight, the emerging and minor experimentations, need to be accelerated. The goal is not to accelerate towards a targeted state, but rather to always allow other becomings to come.

Deleuze and Gattari do not believe in mastery over evolution, but rather in the event; that is, the creation of singularities, the emergence of the new, and encounters of heterogeneous flows capable of inventive arrangements.

In the reactions we have observed in Brazil, there was a multiplication of head-on oppositions but these ran the risk of fueling the accelerating hegemonic government movement. However there was also the multiplication of projects that fed or helped to invent lines of flight, becoming-minor, generating affects of care and solidarity. Vital and inventive forces, in their ability to experiment and create, without pretending to know and guide, form the real alternative. This is not about accelerating towards a future with a well-drawn outline, but about promoting diversity, the construction of one's own voice, and making alternative connections with history than those defined in the dominant narrative. In other words, it is not a question of a counter narrative opposed to the major narrative; but of culture, as a preindividual and virtual, from which to recompose multiple narratives, plural, and unfixed identities.

An uncommon resistance strategy

While it is still too early to assess its effectiveness, we would like to highlight a few key points about the alternative Deleuzian strategy for countering adverse accelerationism in Brazil, and its authoritarian imposition of change. The strategy is a call for a form of critique, a poetics of knowledge, and the embrace of affect and vulnerability; which are characterized by difference with other forms of resistance to acceleration. It is useful to position this strategy within the literature, first on resistance to accelerationism, and, beyond, on resistance to change management.

Critique of critique is a recurring theme of accelerationism. Critique indirectly legitimizes the regime it opposes; and is hereby its accomplice [START_REF] Avanessian | Criticism -Crisis -Acceleration[END_REF]. Critique is often a useless manifestation of leftist 'miserabilism', while the real danger supposedly comes from elsewhere [START_REF] Land | Meltdown[END_REF]. Critique belongs to the realms of speech and law, whereas the strategy we describe and endorse appeals to affects, and impacts on subjectivities.

We still must view critique as an indispensable response, particularly on the part of the university and artists, however we see that critique has led to a tragedy of resistance that fuels and increases adherence to what it has criticized.

The capacity of capitalism to feed on its (artist and political) critique was well demonstrated by [START_REF] Boltanski | Le nouvel esprit du capitalisme[END_REF]. Accelerationism relies precisely on the contradiction whereby anti-capitalism feeds capitalism's ability to renew itself and to progress, speeding up its performative transformation. The strategy we have documented attempts to escape the contradiction that opposition or negativity leads to the strengthening of what it opposes. Our goal is to escape dialectics and to affirm difference. [START_REF] Noys | The Persistence of the Negative: A Critique of Contemporary Continental Theory[END_REF] has criticized contemporary affirmationism, which embraces the immanence of materiality, of bodies and loci of power and production, by affirming creativity and inventiveness; and forgetting the critical role or potential of negativity. Deleuze is indeed the affirmative philosopher par excellence. But in the Brazilian context of the theatre of death, where hatred against all forms of differences prevails, and where repressive politics takes precedence over the liberties of the majority; it is precisely Deleauze's vitalism and celebration of difference and of the minor, as well as the call for joyful experimentation, that sustains the very possibility of opposition.

The strategy that tries to escape the tragedy of resistance is affirmationist; yet it does not seek to impose an image of the future towards which we must accelerate. This is where it differs from the other accelerationist strategies. Indeed, many accelerationists call on artists and academics to step out of their world, and to propose "hyperstitions" or ideas capable of condensing reality and provoking changes in culture, to accelerate towards a systemic shift (e.g. [START_REF] Land | Hyperstition: An Introduction[END_REF][START_REF] Avanessian | Accelerating Academia: On Hyperstition in Theory[END_REF]. The poetics of knowledge is claimed to be capable of redefining the possibilities of speech, having an ethical and political effect [START_REF] Avanessian | Accelerating Academia: On Hyperstition in Theory[END_REF]. But when an idea is oriented towards a single result, and tries to impose itself, the becoming-major of the idea, is at hand. Avanessian (2013, p.60) proposes the formula: "acceleration + direction = progression towards a future."

The reaction we have documented rather calls for a poetics of knowledge, in a sense close to that given by Jacques Rancière. In other words, a call for the production of knowledge that does not fall under the authority of science, that does not claim to tell the only truth, but that appeals to the intelligence of the interlocutor, and to her ability to forge links to her or his own experience. It is not a question of imposing a direction, but of co-participating in the production of sense. The aim is not to re-territorialize becoming in an accelerationist program, where difference and diversity are repressed, but to heighten capability for minor becomings.

Particular attention is to be devoted to affect, memory, relatedness and encounters. Ray [START_REF] Brassier | Accelerationism: Ray Brassier, Moskvax[END_REF], one of the editors of Nick Land's latest book, notes that Nick Land, in his thinking about matter and machinery, was not interested in subjective and affective experience. Land focused on the intensification of intensity, which is not translatable into affective experience, nor even into affective intensity (see [START_REF] Shaviro | Speed Limit: Three Essays on Accelerationism[END_REF]2016).

The Brazilian government is identified with the face of the president and a few other symbolic allied leaders, through what [START_REF] Deleuze | Capitalisme et schizophrénie 2 : Mille plateaux[END_REF] call 'facial machines'. But it refuses to see the faces of the minorities. The vulnerable must become stronger or remain exploited. There are affects involved, very powerful ones, but they are mainly the sad affects of resentment, hatred and anger. Such affects are driven by blind intensity. The micropolitics of resistance, consist then in exposing the faces and histories of the minorities and the vulnerable. The goal is to expose a diversity of faces, voices and affects, to listen to local stories or knowledge, to become-minor by inventing lines of escape. Facing the face of vulnerable others, recomposes the context, disarticulates stereotypes, and disconcerts readymade readings based on moral judgments that do not allow for dissensus. [START_REF] Rancière | Les bords de la fiction[END_REF][START_REF] Rancière | Les temps modernes[END_REF] calls for new possible imaginaries that contradict the usual way of occupying social space. These imaginaries play with the prescribed and embrace the invented and the reassembled. Such deterritorializations reaffirm the ability to invent diverse modes of existence and assemblages.

Instead of asserting fixed identities and claims, and entering into a game of power and of opposition, the Deleuzian response is to see vulnerability and precariousness as the norm. [START_REF] Butler | Precarious Life: The Powers of Mourning and Violence[END_REF][START_REF] Butler | Rethinking Vulnerability and Resistance[END_REF] invites us to re-semanticize the concept of vulnerability, creating new ways of life outside of disciplinary regulation. Vulnerability then reveals a way of being constituted by being affected by occurrence, opening up the ability of agency. [START_REF] Lazzarato | As revoluções do capitalismo[END_REF] suggests that life can be defined as "precarious," wherein identity varies between many names, and for that reason escapes the classificatory mechanisms. The precarious, instead of losing the ability of action, assume a non-institutionalized and non-standardized possibility of multiple emancipatory actions.

The difference with the resistance to capitalist acceleration, proposed by Bifo (we follow [START_REF] Gardiner | Critique of Accelerationism[END_REF], needs to be noted. Franco 'Bifo' Berardi mistrusts 'heroic' resistance and any future-oriented progressivism. He is wary of any project based on people's desires, because these are always already directed by the capitalist machine. He calls for a radical slowing down, based on ironic detachment, and an aesthetic cultivation of experiment. A 'therapy' to heal the exhausted and depressive human organism is required. In the case of today's Brazil, where institutions are under threat from the establishment of an illiberal authoritarian politics, 'slow affectivity' and 'radical passivity' could yet be a dangerous bet.

As [START_REF] Noys | Malign Velocities: Accelerationism and Capitalism[END_REF] argues, it is a matter of resisting assimilation and the jouissance of immersion into a powerful machine. We must attempt collectively to sustain courageous forms of struggle and negation that do not offer false consolation. Resistance cannot only be reactive and oppositional. Accelerationism is ambiguous, because it can be understood in the prescriptive sense of voluntary action or in the descriptive sense of mechanisms at work [START_REF] Henkin | Accelerationism and Acceleration[END_REF].

The defense of the academic and artistic institutions and forms of life would benefit from a combination of activity and passivity, relying on the vital energy of multiple becomings, of affect and proximity; fostering a micro-politics of life at the molar level. It is a question of eliciting already present power, and of affirming what is. Between activity and passivity, we become a weak force and a strong weakness that tries to escape the tragedy of resistance.

Between the two dead-ends of pure becoming achieved through destruction or through abstraction, or an intensity without movement or speed, that remains a pure jouissance, resistance might rather come from arrangements and technologies that seek a resonance and amplification of potentials of groups [START_REF] Huy | A Politics of Intensity: Some Aspects of Acceleration in Simondon and Deleuze[END_REF]. Indeed this resistance to accelerationism is also a form of resistance to change and thus contributes to its discussion. In the literature, the resistance to change has a rather narrow seemingly indisputable meaning up until the 1990's [START_REF] Dent | Challenging "Resistance to Change[END_REF]. Developed from a systemic vision of various force fields [START_REF] Lewin | Field Theory in Social Science[END_REF], the conception was reduced to a negative psychological inclination of employees towards management's initiatives. [START_REF] Mumby | Resistance Redux[END_REF]Mumby et al. ( : 1158) ) note contrastingly, that from 2000, we "have witnessed an explosion of research in and around organizations, with scholars from a variety of theoretical perspectives attempting to get to grips with the dynamics of workplace struggle and other forms of protest."

Resistance has changed its face with neoliberalism, taking on forms which have been variously documented that are more complex and paradoxical. Research on resistance in and to organizations continues to be broadened in four directions, and we see this paper as a contribution to them:  First, there are studies revealing infrapolitical practices, in a context where public displays of resistance might be dangerous. Such practices complement more frontal forms of resistance and give strength to the resisters [START_REF] Courpasson | Beyond the hidden/public resistance divide: How bloggers defeated a big company[END_REF].

 Second, the role of affects, identity work and affirmation outside of power frames are being addressed, showing the narrow line between power's exploitation of resistance [START_REF] Boltanski | Le nouvel esprit du capitalisme[END_REF] and the possibilities of subversion. For example, universities may have to conform backstage, in order to gain more power for their frontstage opposition, and vice versa [START_REF] Ybema | Resistance through compliance: The strategic and subversive potential of frontstage and backstage resistance[END_REF].

 Third, there is documentation of opposition, not only to neoliberalism but to its alliance with conservatism and religious groups, in the context of authoritarian liberalism [START_REF] Chamayou | La société ingouvernable. Une généalogie du libéralisme autoritaire[END_REF] or illiberalism [START_REF] Zakaria | The Future of Freedom: Illiberal Democracy at Home and Abroad[END_REF]. Hereby, the importance of enacting new subjectivities, meanings, and alternative modes of political organizing is emphasized [START_REF] Daskalaki | Organizing solidarity initiatives: A socio-spatial conceptualization, of resistance[END_REF].

 Finally, there is a possible resistance by academics [START_REF] Contu | … The point is to change it' -Yes, but in what direction and how? Intellectual activism as a way of 'walking the talk' of critical work in business schools[END_REF], and by advocates, for the powerless and disadvantaged (Agócs, 1999).

The form of resistance to the destructive acceleration that has been documented is thus part of these new directions in the literature on resistance to change, a resistance that seeks resonance and amplifications in the life powers of groups and institutions.

Conclusion

Confronted in Brazil with an accelerationist policy, opposition to change can paradoxically lead to accelerating it. This places the opponents in a tragic dilemma; it seems impossible not to oppose, but opposing, risks accelerating towards a very undesirable fate. We have documented an alternative strategy: against a power that absorbs and oppresses all difference; the only other strategy seems to consist in accelerating the lines of flight, and empowering multiple efforts at becoming-minor. This strategy resonates with our reading of Deleuze, and tries to circumvent the unethical consequences of Land's accelerationist politics. This is an unusual form of resistance to change. Rather than slowing down or voicing, it is about doing more, better, faster and collectively. There are forces to destroy the university in its universal intention, notably the critical social sciences, as well as a reflexive art about society. So against delegitimisation and fake news, produce well-founded and disseminated information and analysis, against stigmatisation, produce research and works that care and perform active solidarity. Resistance takes many forms, acting through the infrapolitical, the affective, the formation of subjectivities. It does not want to go backwards but to accelerate in the opposite direction. It does not want to lead a counter-change, but to strengthen the living forces that can invent becomings other than those imposed. In contrast to [START_REF] Land | Teleoplexy: Notes on acceleration[END_REF], which sees any resistance to deterritorialisation and abstraction as conservative, the reterritorialisation in the concreteness of faces, landscapes and desires, which strengthens the living forces to recompose assemblages, seems rather a progressivism without teleology. To resist change here is not to slow down but to increase intensities.

It is still difficult to assess the effectiveness of the documented strategy, its conditions for success, and the contexts in which it is relevant. Further research, in both illiberal and nonilliberal contexts, will be needed to better understand the scope and hazardousness of the proposed strategy. There seems to be a way out of the tragedy of resistance, which rebuilds ties to affect, and brings the energy needed to act and to have hope in solidarity. In Zelazni (1967)'s novel, where the term first appeared, the "accelerationists" had a very peculiar strategy. An elitist class of colonizers presented themselves as gods, and ruled according to their interests. Some members of this class, the accelerationists, gave part of their knowledge, powers and substance to those who dwelled below, hence speeding up the development of everyone's god-like status, with the result that "there would no longer be any gods, only men."

Against a machine that wants to galvanize the people into a single body under the figure of a god/master/father, the resistance re-enhances pluralities, becoming, and dignity.

Landian accelerationism, according to Rosa Janis (2018), posits technology as an alien force that consumes all of humanity; revealing aspirations showing the ugliest face of man.

Deleuze distanced himself from humanism, but he invites us to judge ideas according to their effects on modes of existence. Opposing an accelerationist political machine, that aims to unify and control forms of life, we need to protect the vitality of the plurality of modes of existence.

The author warmly thanks Hugo Letiche for his extensive and patient language editing.

All references from https://www.laboriacuboniks.net/index.html(unpaginated)

Intentionally no additional details about the participants, their affiliations or direct quotes from them are provided, to ensure that nothing is revealed that could harm fellow colleagues.


Mhedine Ali Cherif

Victor Lafaurie

Alain Claverie

Svetlana Starikovskaia

Pierre Vidal

Detonability enhancement by use of a nanosecond plasma

Introduction

Detonability is described as the efficiency of ignition or propagation of detonation, although a choice of the most relevant definition is still under debate. Each of these phenomena is represented by its characteristic length, that is, the transition distance from deflagration to detonation (DDT) and the mean width of the cells resulting from the intrinsic instability of the detonation reaction zone. The DDT distance and time represent the rapidity to obtain detonation from a flame generated with a low-energy device, and the cell width represents the capacity for detonation to propagate in a channel of finite transverse dimension. Thus, the smaller the DDT length or the cell width, the greater the detonability. Interest of detonation as a substitute to the usual isobaric combustion process is explained by its high characteristic pressure and short reaction times and lengths. For example, scientific research related to pulsed or rotating detonation engines is very important over the past decades. One of the main issues is to ensure detonation ignition and propagation in a large range of initial conditions because imperfect mixing of fuel and oxidizer, specific initial conditions such as low initial temperatures decrease detonability [START_REF] Kailasanath | Review of propulsion applications of detonation waves[END_REF][START_REF] Kailasanath | Recent developments in the research on pulse detonation engines[END_REF][START_REF] Wolański | Detonative propulsion[END_REF][START_REF] Roy | Pulse detonation propulsion: challenges, current status, and future perspective[END_REF][START_REF] Shepherd | Analytical Models for the Thrust of a Rotating Detonation Engine[END_REF][START_REF] Lee | The detonation phenomenon[END_REF][START_REF] Desbordes | Multi-scaled cellular detonation[END_REF]. This paper presents the results of experiments and calculations that demonstrate that plasma enhances detonability, that is, decreases the DDT length and the cell width. Our work investigates (i) the links between the pre-dissociation of a gas mixture by plasma action and (ii) the decrease of the characteristic times and lengths of the combustion reactions. For the DDT experiments, a nanosecond multichannel capillary discharge was used to ignite the flame. For the experiments on the cellular detonation regime, a nanosecond discharge homogenously distributed was used to pre-dissociate the mixture at the moment of arriving of the detonation wave front.

Experimental setup

For the DDT experiments, the tube was 3.5-m long with cross-section 4x4 cm 2 , and the studied gas was the stoichiometric H 2 :O 2 mixture at 600 -800 mbar. We estimate a specific delivered energy in the capillaries to be as high as about 1 ev/particule. Flame ignition, evolution and transition to detonation were recorded using schlieren imaging. The results were compared to the ignition by a classical automotive spark. For the cellular detonation experiments, the tube was 3.5-m long with crosssection 5x5 cm 2 and the studied gas was the stoichiometric H 2 :O 2 mixture diluted with 40 % of argon. The specific delivered energy in the discharge was about 10 -3 eV/particule in the whole volume defined by the tube cross section and the length of the high-voltage electrode, 20 cm. The plasma effect was analysed from the recordings of the tracks left by the detonation cellular structure on soot-coated plates positioned opposite to the high-voltage electrode, and the electrical parameters of the discharge were recorded using the back current shunt technique.

Results

Figure 1: Ignition and evolution of the flame in the stoichiometric H 2 :O 2 mixture at 600 mbar (Schlieren). Top: nanosecond discharge with the plasma electrode. Bottom: automotive plug.

Figure 1 shows typical Schlieren pictures of the ignition and evolution of the flame in the stoichiometric H 2 :O 2 mixture at 600 mbar. The flame evolution is much faster and its front shows more structures, hence a larger combustion surface, with the nanosecond plasma discharge than with the automotive plug. For example, the fourth picture of the plasma sequence at 141 µs shows that the flame has reached half the field when this position is only reached at 420 µs with the ignition by the automotive plug. As a consequence, the push on the initial mixture is faster and stronger as indicated by the presence of compression waves ahead of the front (the dark vertical lines at the rightmost part of the picture at 141 µs. The flame shows several combustion kernels, generated by the multiple-point electrode, hence a more turbulent front. In contrast, the flame front obtained with the automotive plug always shows a smooth surface in the frame time of the recordings. The plasma ignition thus leads to a faster and more turbulent flame that speeds up the transition to detonation (fig 3, left). Figure 2 shows soot recordings corresponding detonation experiments in the H 2 :O 2 mixture at 150 mbar diluted with 40% of argon. The zone over which plasma was triggered is indicated by the "P" for the middle and the right plates in 2. A decrease of the detonation cell width is easily observed by comparison with the cells on the reference The principle of the numerical analysis of the detonation experiments was (i) to carry out a 0D calculation of the pre-dissociated initial state using a plasma kinetic scheme; (ii) to use the results of the calculations as input for a ZND code implementing a detailed chemistry of H 2 -based mixtures [START_REF] Mevel | Fundamental combustion properties of oxygen enriched hydrogen/air mixtures relevant to safety analysis: Experimental and simulation study[END_REF]; (iii) to obtain the temperature profiles in the detonation reaction zone. Indeed, as a first approximation, the ZND induction distance is proportional to the mean cell width. Figure 4 shows the temperature profiles at 150 mbar for the stoichiometric H 2 :O 2 mixture diluted with 40% of argon, without (left) and with (right) plasma pre-dissociation. The plasma-case profile was calculated with 2% atomic oxygen added to the initial composition, a number given by the 0D calculations. We observe a reduction of the induction time by a factor of 2, a ratio that agrees with the experimental reduction of the detonation cell size. We found that the ignition of a flame with a multichannel plasma nanosecond discharge produces a stronger and more turbulent flame that evolves faster into detonation than a flame obtained with an automotive plug. We also found that the pre-dissociation of the initial composition by application of a plasma nanosecond discharge ahead of a detonation front immediately modifies the wave structure by reducing the size of the detonation cells. This demonstrates experimentally that plasma can enhance detonability defined as either the DDT distance or the cell width. The calculated effect of plasma pre-dissociation on the induction time in the ZND detonation agrees with the measured decrease of the detonation cell width. The DDT distances are known to be very sensitive to the tube length, roughness and constitutive material. To a lesser extent, this also applies to the detonation cellular structure if the transverse dimension of the tubes is too small because the detonation combustion time is much smaller than that of the DDT development. The results obtained in our study should thus be considered as restricted to our conditions. However, because our experimental design and configurations are fundamentally simple, our conclusion is that specific devices implementing detonation as a combustion process could be more efficient and compact by using plasma actions.

Acknowledgement

The work was supported by the DGA (convention EP-DGA N2790)

Figure 2 :

 2 Figure 2: Soot recordings of the detonation cellular structure without (left) and with (middle and right) plasma pre-dissociation for the stoichiometric H 2 :O 2 mixture at 150 mbar diluted with 40% of argon.

Figure 3 :

 3 Figure 3: Measured DDT distances (left) and detonation cell widths (right) without and with plasma pre-dissociation for the stoichiometric H 2 :O 2 mixture at 150 mbar diluted with 40% of argon

Figure 4 :

 4 Figure 4: Calculated ZND profiles without (left) and with (right) plasma pre-dissociation for the stoichiometric H 2 :O 2 mixture at 150 mbar diluted with 40% of argon

Correspondence to: mhedine.alicherif@lpp.polytechnique.fr

th ICDERS -June 19 -24, 2022 -Napoli, Italy