Greifswald 2009 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 9: Sun III and Heliophysics I
EP 9.10: Talk
Wednesday, April 1, 2009, 16:15–16:30, Zahnklinik
Simulation of the preferential heating and acceleration of alpha-particles by Alfven-cyclotron waves — •Yana Maneva1, Jaime Araneda2, and Eckart Marsch1 — 1Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau — 2Departamento de Fisica, Universidad de Concepcion, 4070386, Chile
The observed preferential heating and acceleration of heavy ions in the solar corona and solar wind represent a long-standing theoretical problem in space physics, and are distinct experimental signatures of kinetic processes occurring in a hot collisionless plasma. Here we show that fast and slow ion-acoustic waves (IAW) and transverse cyclotron waves, driven by parametric instabilities of an Alfven-cyclotron wave train can selectively destroy the coherent fluid motion of the different ion species, and in this way, lead to their differential heating and acceleration. Trapping of the lighter and more abundant protons by the fast IAW generates a field-aligned proton beam with a drift speed of about the Alfven speed, consistently with observations. Due to their larger mass and lower plasma beta, the alpha-particles do not become significantly trapped and start, by conservation of total ion momentum, drifting relative to the receding bulk protons. Thus the resulting core protons and the alpha-particles are differentially heated via pitch-angle scattering by the transverse waves.