Nonlinear evolution of the electromagnetic electron-cyclotron instability in bi-Kappa distributed plasma

B. Eliasson, M. Lazar

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This paper presents a numerical study of the linear and nonlinear evolution of the electromagnetic electron-cyclotron (EMEC) instability in a bi-Kappa distributed plasma. Distributions with high energy tails described by the Kappa power-laws are often observed in collision-less plasmas (e.g., solar wind, accelerators), where wave-particle interactions control the plasma thermodynamics and keep the particle distributions out of Maxwellian equilibrium. Under certain conditions, the anisotropic bi-Kappa distribution gives rise to plasma instabilities creating low-frequency EMEC waves in the whistler branch. The instability saturates nonlinearly by reducing the temperature anisotropy until marginal stability is reached. Numerical simulations of the Vlasov-Maxwell system of equations show excellent agreement with the growth-rate and real frequency of the unstable modes predicted by linear theory. The wave-amplitude of the EMEC waves at nonlinear saturation is consistent with magnetic trapping of the electrons.
Original languageEnglish
Article number062109
Number of pages9
JournalPhysics of Plasmas
Issue number6
Publication statusPublished - 15 Jun 2015


  • electromagnetic electron-cyclotron instability
  • bi-Kappa distributed plasma
  • numerical simulations

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