Reading Solar System Science 2020

In Reading Solar System Science, we propose five independent projects to gain further insight and understanding in solar and heliospheric physics, magnetospheric plasma processes and planetary atmospheres. Our research will address questions important to how our Sun works, how its variability affects the solar system, the science of space weather, and the existence of life on other planetary bodies.

The solar wind is the term given to the outer atmosphere of the Sun, which is constantly expanding through the solar system and blowing across the planets like a wind. We will use physics-based models and data assimilation to make the first reconstruction of the structure of the solar wind over many decades. This reconstruction can then be probed to discover more about the generation of the solar wind.

The solar wind carries the magnetic field from deep within our star out into the solar system. This field forms closed loops (with both ends at the Sun) and "open" threads, where only one end originates at the Sun. Different independent measures of how much "open" magnetic field exists in the heliosphere provide different estimates of the amount of open field (known as "open solar flux") that exists; we will use a large number of new and old in-situ spacecraft measurements to attempt to explain the discrepancy.

Periodically, the Sun emits large bubbles of plasma into the solar wind, known as coronal mass ejections (CMEs). These bubbles flow through the solar wind, interacting with it and changing shape and speed. We will use imaging data, some of which has been processed by citizen scientists, along with physics-based models to infer the changes in CMEs as they propagate through different solar wind scenarios. We will employ a novel technique to probe how the density of CMEs changes in transit too.

Closer to the Earth, the energetic electrons in the radiation belts that surround the Earth are controlled in part by interactions with a wide range of electromagnetic waves. We have a useful theoretical description of the strength of these wave-particle interactions, but it was only designed for waves that do not vary much in time. Real-world observations indicate that the waves and plasma conditions are highly variable and so we look to run physics-based numerical experiments to identify how we should use our knowledge of wave-particle interactions to better model the behaviour of the radiation belt.

Finally, we will build analogues of the Martian atmosphere in the laboratory in order to better understand the behaviour of charged dust particles and dust devils in the Martian atmosphere. The arid environment of Mars supports the formation of dust devils that are much larger and stronger than those found on Earth, and we propose to recreate conditions for their formation in the lab, in order to better understand how these atmospheric phenomena affect the distribution of methane. Importantly, methane could provide one of the clues to the existence of life on the planet.