Ion Acceleration in Plasmas with Alfvén Waves
Authors: Oleh Kolesnychenko, Vadym Lutsenko, and Roscoe B. White
Date of PPPL Report: June 2005
Submitted to: Physics of Plasmas
Effects of elliptically polarized Alfvén waves on thermal ions are investigated. Both regular oscillations and stochastic motion of the particles are observed. It is found that during regular oscillations the energy of the thermal ions can reach magnitudes well exceeding the plasma temperature, the effect being largest in low-beta plasmas (beta is the ratio of the plasma pressure to the magnetic field pressure). Conditions of a low stochasticity threshold are obtained. It is shown that stochasticity can arise even for waves propagating along the magnetic field provided that the frequency spectrum is non-monochromatic. The analysis carried out is based on equations derived by using a Lagrangian formalism. A code solving these equations is developed. Steady-state perturbations and perturbations with the amplitude slowly varying in time are considered.