Measuring Collisionless Damping in Heliospheric Plasmas using Field-Particle Correlations

TL;DR

This paper introduces a new field-particle correlation method that uses single-point measurements to analyze energy transfer and damping mechanisms in collisionless plasmas like the solar wind, with potential applications in spacecraft data analysis.

Contribution

It presents a novel technique for diagnosing collisionless damping in plasmas using single-point measurements, enhancing analysis of turbulent energy transfer in space plasmas.

Findings

Successfully estimates local energy transfer rates in plasma simulations.

Identifies the resonant nature of Landau damping in a simplified plasma model.

Discusses modifications for spacecraft measurements to study solar wind turbulence.

Abstract

An innovative field-particle correlation technique is proposed that uses single-point measurements of the electromagnetic fields and particle velocity distribution functions to investigate the net transfer of energy from fields to particles associated with the collisionless damping of turbulent fluctuations in weakly collisional plasmas, such as the solar wind. In addition to providing a direct estimate of the local rate of energy transfer between fields and particles, it provides vital new information about the distribution of that energy transfer in velocity space. This velocity-space signature can potentially be used to identify the dominant collisionless mechanism responsible for the damping of turbulent fluctuations in the solar wind. The application of this novel field-particle correlation technique is illustrated using the simplified case of the Landau damping of Langmuir waves in an electrostatic 1D-1V Vlasov-Poisson plasma, showing that the procedure both estimates the local rate of energy transfer from the electrostatic field to the electrons and indicates the resonant nature of this interaction. Modifications of the technique to enable single-point spacecraft measurements of fields and particles to diagnose the collisionless damping of turbulent fluctuations in the solar wind are discussed, yielding a method with the potential to transform our ability to maximize the scientific return from current and upcoming spacecraft missions, such as the Magnetospheric Multiscale (MMS) and Solar Probe Plus missions.