Vlasov-Poisson simulations of electrostatic parametric instability for localized Langmuir wave packets in the solar wind

TL;DR

This paper uses Vlasov-Poisson simulations to investigate the electrostatic parametric instability of Langmuir wave packets in the solar wind, providing insights into solar radio emission mechanisms.

Contribution

It presents the first kinetic simulation-based threshold analysis of Langmuir wave decay in solar wind conditions, aligning with observed wave amplitudes.

Findings

Observed wave amplitudes match the simulated instability threshold.

Ion acoustic fluctuations are consistent with observational data.

The study supports the role of parametric decay in solar radio emissions.

Abstract

Recent observation of large amplitude Langmuir waveforms during a Type III event in the solar wind have been interpreted as the signature of the electrostatic decay of beam-driven Langmuir waves. This mechanism is thought to be a first step to explain the generation of solar Type III radio emission. The threshold for this parametric instability in typical solar wind condition is investigated here by means of 1D-1V Vlasov-Poisson simulations. We show that the amplitude of the observed Langmuir beat-like waveforms is of the order of the effective threshold computed from the full kinetic simulations. The expected level of associated ion acoustic density fluctuations have also been computed for comparison with observations.