Hybrid Simulation Of Alfvén Wave Parametric Decay Instability In Laboratory Plasmas

Abstract

Nonlinear Alfvén waves are subject to parametric instabilities. The parametric decay instability (PDI) is of special interest as it produces backward propagating Alfvén waves which may trigger turbulence development and generates compressible waves which may cause plasma heating. Despite the significant implications, the PDI process has not been directly verified. Recent experiments on the Large Plasma Device (LAPD) showed a modulational-like instability [1] . However, the PDI was missing despite its significant growth rates under the conditions investigated. To resolve the puzzle, we are developing hybrid simulation capabilities to investigate the LAPD-type experiments with realistic geometry and physics conditions. As a first step, we relax the usual periodic boundary conditions and study the PDI of an Alfvén wave packet in a large system under an absorption boundary [2] . We further consider the LAPD-like wave injection and outline the conditions required for observing the PDI in a laboratory plasma [3] . These results may guide the first laboratory verification of the fundamental PDI physics and shed lights on several problems in the heliosphere such as corona/solar-wind heating.