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Session 18 - Flares I.
Oral session, Tuesday, July 01
Ballroom A, Chair: Mona Hagyard

[18.04] Stochastic Acceleration of Low Energy Electrons in Plasma with Finite Temperature

J. Pryadko (Stanford University), V. Petrosian (Stanford University)

In this paper we extend our earlier work (Pryadko and Petrosian, ApJ. 1997, vol.482) on the acceleration of low-energy electrons by plasma turbulence to include the effects of finite temperature of the plasma. We consider the resonant interaction of such electrons and the whole transverse branch of plasma waves propagating along the magnetic field. The importance of the plasma parameter \alpha = ømega_pe/Ømega_e (the ratio of electron plasma frequency to electron gyrofrequency) in the dynamics of the charged particles is emphasized. We show that our earlier published results for acceleration of low-energy electrons can be applied to the case of finite temperature if the sufficient level of turbulence is present. From comparison of the acceleration rate of the particles with the decay rate of the waves they interact with, we determine the energy density of waves, as a fraction of the magnetic energy density, required for acceleration of a substantial fraction of the background plasma electrons. The dependence of this value on the plasma and turbulence parameters is described through the numerical results. The approximate analytical expression is derived for the case of super-thermal electrons.

This work was supported by NSF grant ATM 93-11888 and NASA grants NAGW 1976 and 2FEX404.


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