# The Parametric Decay Instability of Alfven waves in Turbulent Plasmas and the Applications in the Solar Wind

## TL;DR

This study uses 3D MHD simulations to analyze the parametric decay of Alfven waves in turbulent plasmas, revealing insights into solar wind wave generation and the influence of turbulence on wave decay.

## Contribution

It demonstrates that Alfven waves can undergo parametric decay in turbulent conditions, with reduced growth rates, and links this process to slow wave generation in the solar wind.

## Key findings

- Parametric decay occurs across various turbulence amplitudes.
- Growth rates are lower in turbulent plasmas than in non-turbulent cases.
- Density fluctuations match slow MHD wave dispersion relations.

## Abstract

We perform three dimensional (3D) ideal magnetohydrodynamic (MHD) simulations to study the parametric decay instability of Alfven waves in turbulent plasmas and explore its possible applications in the solar wind. We find that, over a broad range of parameters in background turbulence amplitudes, the parametric decay instability of an Alfven wave with various amplitudes can still occur, though its growth rate in turbulent plasmas tends to be lower than both the theoretical linear theory prediction and that in the non-turbulent situations. Spatial - temporal FFT analyses of density fluctuations produced by the parametric decay instability match well with the dispersion relation of the slow MHD waves. This result may provide an explanation of the generation mechanism of slow waves in the solar wind observed at 1 AU. It further highlights the need to explore the effects of density variations in modifying the turbulence properties as well as in heating the solar wind plasmas.