Ion acoustic turbulence driven by return current leads to hot electrons in laser-produced plasma

Abstract

The instability of ion acoustic waves due to the return current driven by an electron heat flux is a source of ion acoustic turbulence (IAT), which provides electromagnetic wave conversion into Langmuir waves at a near-critical density in inertial confinement fusion plasmas. The Langmuir waves triggered by IAT produce hot electrons. We formulate a theoretical model of hot-electron generation by these Langmuir waves and analyze it qualitatively. We show that IAT-driven hot electrons are generated in the backward direction and, therefore, preheat the target core because of the electron refluxing in the coronal plasma back toward the solid target.