The Interaction Between Solar Wind Electrons and Electrostatic Instabilities

Jingting Liu

Supervisors:  Daniel Verscharen, Hamish Reid, Georgios Nicholas

The solar wind is a fully ionised and quasi-neutral plasma flow which carries a variety of waves as quasi-periodic fluctuation in the particle quantities and the electromagnetic fields. Particles and fields can exchange energy when the plasma particles interact with fluctuations in the solar wind. This energy transfer process is one of the biggest challenges in studies on space plasma and directly relates to the mystery of collisionless plasma heating.

My research explores the interaction between electrons and electrostatic instabilities. I project use Particle-In-Cell (PIC) simulations, quasilinear theory, and kinetic theory to uncover the complex mechanisms underlying wave-particle interactions and instabilities in the solar wind. I am particularly interested in understanding how these processes drive instabilities and influence energy distribution in space environments. By integrating theoretical models with advanced simulation techniques, this project bridges fundamental plasma physics with observational data, contributing to a deeper understanding of the heliosphere and its impact on planetary systems.

My recent projects are on magnetic inhomogeneities. We present a novel kinetic multi-scale model for Langmuir-wave excitation in MHs, based on the conservation and violation of the electron magnetic moment. Our model illustrates that MHs can induce changes in the electron velocity distribution function that emit electrostatic Langmuir waves due to the bump-on-tail instability. Using in-situ measurements from the Solar Orbiter mission, we validate our theoretical predictions and demonstrate strong agreement between the modelled dynamics and observed wave activity. Our results highlight the importance of the multi-scale coupling of localized magnetic structures in driving kinetic processes in the solar wind and offer a mechanism that connects ion-scale magnetic inhomogeneities to electron-scale wave excitation.