Jordi Boldu & Daniel Graham (IRF Uppsala): Probing the evolution of the solar wind using kinetic waves (Introduction Seminar)

Thursday 3 Feb 2022, 14:00 → 15:00 Europe/Stockholm

https://uu-se.zoom.us/j/62091586806

Title: Probing the evolution of the solar wind using kinetic waves
Speaker: Jordi Boldu & Daniel Graham
Affiliation: IRF Uppsala
Time: Thursday 3 February 2022, 1400 to 1500
Location: online at https://uu-se.zoom.us/j/62091586806 (Zoom meeting ID: 620 9158 6806)

Abstract:

The solar wind is a stream of charged particles from the Sun's corona. As the Sun rotates, the solar wind becomes a complex spiral structure of fast and slow flows. This solar wind interacts with planetary magnetospheres and can generate space weather events. The solar wind is naturally a turbulent plasma environment where the unstable electron and ion distributions readily occur. As a result, various kinetic waves can be generated, scatter particles, and potentially transfer energy between different particle species. Various waves can be excited from non-Maxwellian electron and ion distributions, such as Langmuir waves, ion-acoustic waves, electrostatic solitary waves, whistler waves, lower hybrid waves, and Alfven waves. What waves significantly contribute to the particle scattering processes are still open questions. Of special interest are the Langmuir waves (electrostatic waves near the electron plasma frequency), which are often observed in the solar wind. The largest amplitude waves are typically associated with type II and III solar radio bursts and planetary foreshocks. However, Langmuir waves not connected with radio bursts are also found in the solar wind. The causes of these Langmuir waves are not well understood. Langmuir waves are also found around magnetic holes, a localised depression of the magnetic field strength. We investigate the relationship between Langmuir waves and magnetic holes in the solar wind using electric and magnetic field measurements performed by the Solar Orbiter’s RPW and MAG instruments during 2020. We identified a large set of Langmuir wave events from the RPW/TDS (Time Domain Sampler) waveform data using the plasma density estimated from the spacecraft’s potential obtained by RPW, showing that ~7% of them have been spotted inside magnetic holes.