Symmetry Properties of Proton Velocity Distributions: a Vlasov Simulation Study of the Ion Cyclotron Instability

Wednesday, 17 December 2014
Jaime A Araneda1, Rodrigo A López1 and Adolfo F. Vinas2, (1)Univ. Concepcion, Concepcion, Chile, (2)NASA Goddard Space Flight Center, Heliophysics Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, MD, United States
The ion cyclotron instability is driven by a sufficiently large proton temperature anisotropy, generating a spectrum of counterpropagating field-aligned ion cyclotron fluctuations. In this work, we use low-noise one-dimensional electromagnetic Vlasov simulations in a magnetized and collisionless plasma of fluid electrons and one ion species to study the evolution of proton velocity distributions during the thermal relaxation process. Special attention is given to deviations from initial bi-Maxwellian shapes.