Fundamental plasma physics of the sun and heliosphere: Warwick CFSA Consolidated Grant Application

Quantitative understanding of the fundamental physical processes acting in the Sun's corona and solar wind is essential not only to the physics of the Sun and its connection to the Earth's environment, but it also enhances our knowledge of astrophysical plasma processes in general. Coronal MHD waves are of direct relevance to much of the dynamics such as solar flares and eruptions and carry unique information about the plasma parameters and physical processes operating in it; coronal waves are capable of transferring energy and mechanical momentum from the convection zone into the corona and heliosphere and are associated with the development of plasma instabilities. The plasma flowing out from the sun generates a solar wind. The texture and dynamics of the solar wind is intimately connected to that of the solar corona and this highly variable plasma flow can lead to local heating which in turn accelerates the solar wind. The solar wind is accelerated to such an extent that it is in principle a turbulence laboratory so that quantifying its fluctuations has direct implications for our understanding of turbulence. Solar wind variability is thus a subtle interplay between variability originating in the corona, and turbulent evolution in-situ. Quantifying and understanding the fluctuating solar wind also provides an important input into models for the propagation of cosmic rays in the heliosphere, and for space weather for which the solar wind is the driver. The Sun's magnetic field is generated and maintained by a dynamo in the solar interior. Helioseismology offers a means by which we can probe beneath the visible surface of the Sun, discerning conditions in the Sun's convection zone, constraining uncertain dynamo models and providing vital insights into the internal magnetic field that is ultimately responsible for the more readily observable manifestations in the solar atmosphere and beyond. A quantitative understanding of these processes, closely coupled to observations, can be seen as either the means to understanding observed phenomena, or as using the observed phenomena as a strong drive to understanding new fundamental plasma physics. These ideas, techniques and expertise that underpin this programme are thus of impact beyond plasma astrophysics.