Energy and Momentum Deposition to Plasmas due to the Lower Hybrid Wave by a Finite Source

Abstract

Heating and current generation due to the lower hybrid wave are studied using particle simulation. In contrast with previous work, where only a single mode is treated, the main interest of this work is focused on the physical problems of a propagation cone consisting of many Fourier‐expanded modes. It is found that the trajectory of the propagation cone is well described up to the lower hybrid resonance layer using both the cold plasma approximation and the WKB method. An ion cross‐field drift due to the ponderomotive force is observed. A main discovery of this work is that the modes in the upper portion of the spectrum of the antenna play a key role in the creation of the ion high‐energy tail. This process cannot be explained by the linear theory and is called the cascade process judging from the time variation of the damping of each mode. The particle model is significantly improved using the elongated grid and the quadratic spatial interpolation. Applications of this model to simulations of other probl...