Acceleration of Particles in Imbalanced Magnetohydrodynamic Turbulence

Abstract

The present work investigates the acceleration of test particles in balanced and imbalanced Alfvénic turbulence, relevant to the solar-wind problem. These turbulent states, obtained numerically by prescribing the injection rates for the ideal invariants, are evolved dynamically with the particles. While the energy spectrum for balanced and imbalanced states is known, the impact made on particle heating is a matter of debate, with different considerations giving different results. By performing direct numerical simulations, resonant and non-resonant particle accelerations are automatically considered and the correct turbulent phases are taken into account. For imbalanced turbulence, it is found that the acceleration rate of charged particles is reduced and the heating rate diminished. This behaviour is independent of the particle gyroradius, although particles that have a stronger adiabatic motion (smaller gyroradius) tend to experience a larger heating.

5 pages 6 figures

References in corpus (4)

• Role of cross helicity in magnetohydrodynamic turbulence
• Rapid directional alignment of velocity and magnetic field in magnetohydrodynamic turbulence
• Stochastic Acceleration in Turbulent Electric Fields Generated by 3-D Reconnection
• The Turbulent Heating Rate in Strong MHD Turbulence with Nonzero Cross Helicity