Heliospheric and Planetary Research 2020-2023

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We will conduct a programme of research concerning the solar wind in the inner heliosphere and the dynamics of the rings and satellites of Saturn.The Parker Solar Probe spacecraft was launched in August 2018, and will spend 7 years sampling the Sun's plasma, the solar wind, from closer and closer to the solar surface. In the last part of its mission it will be less than 10 solar radii from the Sun, and then could be truly said to be "touching the Sun." This incredibly challenging mission will revolutionize our view of how the Sun's plasma flows from the corona and fills the space of what is called the heliosphere. The solar wind is also the link between the Sun and the Earth, driving the Space Weather that controls the Earth's magnetosphere, and which can have profound effects on technological systems such as satellites and communication networks. The solar wind is hot (much hotter than the surface of the sun), and has a supersonic flow. We will use data from Parker Solar Probe to characterize the solar wind in the inner heliosphere, and show how it changes with distance from the Sun. We will carry out a coordinated programme of research using data analysis and state-of-the-art plasma simulations to reveal the plasma dynamics of the inner heliosphere. This will help us to solve long-standing problems about coronal heating and the acceleration of the solar wind. For example, plasma turbulence is ever-present in the solar wind, and understanding how it contributes to plasma heating, through a cascade of energy from large to small scales, is a key problem in astrophysics. Our results will help us understand how the solar wind flows from Sun and fills the heliosphere. We will also use our results to understand the operation and role of fundamental plasma processes, such as turbulent dissipation, plasma instabilities and shock acceleration, in space and astrophysical plasmas. The outer part of Saturn's main rings is a region where there is an approximate balance between forces that disrupt bodies (tides) and those that bring them together (self-gravity). Here objects can form, interact with surrounding material and even break up due to collisions. We will use the trove of Cassini images to understand these processes and the role of nearby moons. Studying these mechanisms gives a wider insight into planetary formation and evolution. Images of Saturn's moons against background stars over the duration of the mission will continue to be used to place constraint's on models of Saturn's interior while studying the moons' shapes will give us information about their internal structure.