Regan, Catherine Elizabeth;
(2024)
The Influence of Dust Storms on the
Induced Magnetosphere of Mars.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Dust season on Mars occurs during the perihelion of Mars's orbit around the Sun when the southern hemisphere is in summer season. During this time, regional storms occur every year impacting large parts of the Martian surface. Occasionally, these storms can grow and merge into a singular storm system that covers the entire surface in a planet encircling event, referred to as a global scale dust storm. These do not occur every Mars year, and last happened in 2018, 2007 and 2001 (Mars Year 34, 28 and 25, respectively). A global dust storm typically lasts several months and covers the entire planet in a dusty haze, impacting the surface, atmosphere, and robotic exploration of Mars. I investigate whether these events and processes have an effect at higher altitudes in the induced magnetosphere of Mars, through studies of two boundaries - the bow shock and induced magnetospheric boundary (IMB) during the two most recent global storms (2007 and 2018). I create a boundary catalogue of crossings using data from the Mars Express and MAVEN satellites. Applying this to a 2D empirical boundary model, I find that both boundaries' positions become more variable due to the global dust storms, and the IMB dips closer to Mars over crustal magnetic fields, which is in contrast to its usual behaviour, bulging in these areas. A possible mechanism to cause this is the transport of ionised particles back towards the planet along crustal magnetic field lines which then recombine, reducing the ionospheric pressure here. I also conclude that 3D magnetohydrodynamical models are not suited for this type of study. These results demonstrate that not enough is known about how the global system behaves during dust storms, giving hints to strong coupling mechanisms between the surface, atmosphere and magnetosphere at Mars.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | The Influence of Dust Storms on the Induced Magnetosphere of Mars |
| Language: | English |
| Additional information: | Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10195725 |
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