Event Details

Solar Wind Science with Solar Orbiter

Abstract: Solar Orbiter will soon explore the highly dynamic solar wind plasma within a wide range of heliocentric distances. The Solar Wind Analyser (SWA) suite, on board Solar Orbiter, consists of state-of-the-art plasma instruments to observe the different solar wind components: electrons, protons and heavier ions. Each population will be measured and have their velocity distribution functions determined. In order to understand physical mechanisms in the dynamic solar wind environment we must obtain high time resolution measurements, which will allow an accurate determination of the plasma bulk properties, such as density, speed, and temperature. The accuracy of the determined bulk properties is crucial for a valid and meaningful scientific analysis. In this seminar, I present the SWA’s proton and electron plasma analysers and I explain their measurement principle. I demonstrate the predicted performance of the instruments in the dynamic solar wind by modelling their response based on the initial calibration. Our simulations quantify the expected accuracy in turbulent solar wind plasma which is very challenging to sample due to high frequency fluctuations. This work also explores optimal analysis methods in cases in which the expected plasma flow is very low. I then explain how we plan to understand the solar wind plasma heating/cooling mechanisms through the polytropic behaviour of the plasma species. I discuss our recent results on the determination of the polytropic relationship in solar wind plasma using data from previous missions, such as Wind and Parker Solar Probe. I finally explain how future Solar Orbiter measurements will complement these investigations.