Space Plasma and Magnetospheric Physics at Southampton (2021-4)

This Consolidated Grant application proposes research which will be undertaken at the University of Southampton in three related projects, all of which are connected to the manner in which the Earth's magnetosphere and bow shock respond to the solar wind. The first project will address questions about how the Earth's magnetosphere responds to the solar wind on a large scale. The nature of this interaction depends on the orientation of the interplanetary magnetic field, which is associated with the solar wind. This orientation is highly changeable, but can be referred to as 'northward' or 'southward'. We will use satellite observations to test mechanisms that have been advocated for previously observed complex structure in the magnetosphere during periods when the interplanetary magnetic field is 'northward', to hunt for the signature of that structure's predicted interaction with the solar wind, and to investigate equivalent structure present in global simulations of the magnetosphere. The second project will investigate how a process called 'turbulence' affects shock wave in plasmas. Turbulence is a process whereby chaotic flow causes energy to be transferred from large scales (e.g. the bulk flow of the solar wind) down to small scales (heating individual particles). A shock wave is formed when an obstacle (such as a magnetosphere) is present in a fast-flowing plasma (such as the solar wind). We will use a combination of observations from three satellite missions: MMS, which makes measurements of the plasma environment near Earth in unprecedented detail, and Parker Solar Probe & Solar Orbiter, both of which make measurements of the solar wind closer to the Sun than ever possible before. By combining spacecraft data with high-performance computational simulations, we will determine how the turbulence process and other solar wind transients affect the structure of plasma shock waves. The final project will investigate the link between plasma turbulence observed in the magnetosphere and turbulent structure that is present in the aurora (northern lights) when the aurora is observed on very fine scales. The plasma turbulence will be observed using measurements from MMS (as in Project 2, but this time looking at a different region of the magnetosphere), and the auroral turbulence will be observed using a unique auroral instrument called ASK, which is operated by the University of Southampton. ASK is capable of observing structure in the aurora down to scales of tens of metres, and changes on timescales down to fractions of a second - capabilities that are unique to ASK.