Statistical Properties of Dissipative MHD Accelerators

Abstract

Abstract. We use exact orbit integration to investigate particle acceleration in a Gauss field proxy of magnetohydrodynamic (MHD) turbulence. Regions where the electric current exceeds a critical threshold are declared to be 'dissipative' and endowed with super-Dreicer electric field EΩ = ηj. In this environment, test particles (electrons) are traced and their acceleration to relativistic energies is studied. As a main result we find that acceleration mostly takes place within the dissipation regions, and that the momentum increments have heavy (non-Gaussian) tails, while the waiting times between the dissipation regions are approximately exponentially distributed with intensity proportional to the particle velocity. No correlation between the momentum increment and the momentum itself is found. Our numerical results suggest an acceleration scenario with ballistic transport between independent 'black box' accelerators.

Magnetic Complexity, Fragmentation, Particle Acceleration and Radio Emission from the Sun

“…5b). These jumps are random and their characteristics are shown to be beyond the quasilinear analysis described by the standard Fokker-Planck equation [25]. We can then conclude that for high amplitude MHD waves the simple division between waves, shocks and large scale UCS is lost, and it is replaced with particle acceleration in a mixture of waves, UCS and shocks.…”