Alfven Wave Collisions, The Fundamental Building Block of Plasma Turbulence III: Theory for Experimental Design

TL;DR

This paper discusses the theoretical basis for designing the first laboratory experiment to measure Alfven wave collisions, which are fundamental to plasma turbulence, by analyzing nonlinear energy transfer between counterpropagating waves.

Contribution

It provides a theoretical framework for experimental design to observe nonlinear Alfven wave interactions in a laboratory setting.

Findings

Design of an experiment to measure Alfven wave collisions

Predicted properties of nonlinearly generated daughter waves

Test suite for confirming nonlinear interactions

Abstract

Turbulence in space and astrophysical plasmas is governed by the nonlinear interactions between counterpropagating Alfven waves. Here we present the theoretical considerations behind the design of the first laboratory measurement of an Alfven wave collision, the fundamental interaction underlying Alfvenic turbulence. By interacting a relatively large-amplitude, low-frequency Alfven wave with a counterpropagating, smaller-amplitude, higher-frequency Alfven wave, the experiment accomplishes the secular nonlinear transfer of energy to a propagating daughter Alfven wave. The predicted properties of the nonlinearly generated daughter Alfven wave are outlined, providing a suite of tests that can be used to confirm the successful measurement of the nonlinear interaction between counterpropagating Alfven waves in the laboratory.