Experiment and simulations of kinetic instabilities in mirror-confined ECR discharge plasma

Eliasson, B. and Viktorov, M. and Golubev, S. and Speirs, D.C. and Mansfeld, D. and Phelps, A.D.R. and Bingham, R. and Cross, A.W. and Ronald, K. (2019) Experiment and simulations of kinetic instabilities in mirror-confined ECR discharge plasma. In: 5th Microwaves in Plasmas and Beams Workshop, 2019-12-04 - 2019-12-05, University of Strathclyde.

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    Abstract

    Non-Maxwellian electron distribution functions give rise to a rich variety of kinetic instabilities, such as streaming instability, Weibel instability, and electrostatic and electromagnetic cyclotron instabilities. Electron ring-like distributions are ubiquitous in space plasmas and also occur in mirror-confined plasma where the loss-cone cuts a 'hole' in the distribution function. We report recent observations and simulations of instabilities in mirror-confined ECR discharge plasma [1], where excitation on harmonics and half-harmonics of the electron cyclotron frequency have been observed. The relevance to space plasma are also discussed where similar observations by satellites are common [2,3]. Theory and simulations show that electrostatic instabilities take place where two electron Bernstein modes merge [4]. Electromagnetic Vlasov simulations also show the coupling between electrostatic and electromagnetic electron Bernstein modes leading to instabilities near cyclotron harmonics.