On the rate of energy deposition by an ion ring velocity beam

Abstract

Using a novel three-dimensional electromagnetic hybrid code, XHYPERS, we simulate the generation of lower hybrid oscillations in a magnetized plasma by a heavy ion beam with a ring-shaped velocity distribution over much longer periods of time compared to previous simulations. We introduce a phenomenological (effective) electron damping to represent the induced scattering of lower-hybrid waves to whistlers and the loss of energy through whistler propagation out of the turbulent region. We demonstrate the effective electron damping to be a crucial factor in increasing the efficiency of energy deposition by an ion ring velocity beam into plasma turbulence and investigate the efficiency of beam energy extraction as a function of the electron damping rate and beam to plasma ion mass ratio.