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Investigations of charged particle dynamics in the inner magnetosphere

Mohan, Kirthika; (2017) Investigations of charged particle dynamics in the inner magnetosphere. Doctoral thesis (Ph.D), UCL (University College London). Green open access

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Several authors have reported inner magnetosphere observations of electron and proton distributions confined to narrow energy bands in the range 1 - 25 keV (e.g Smith and Hoffman (1974)). These structures have been described as “nose structures”, with reference to their appearance in energy-time spectrograms, and are also known as “bands” if they occur for extended periods of time. These structures have been explained in terms of the competing magnetic and electric drifts (ions only; e.g. Buzulukova et al. (2003)), possible charge exchange losses in slow drift paths (ions only; e.g. Kistler et al. (1989)) and trapped injected populations (electrons + ions; e.g. Liemohn et al. (1998)). We analyse observations of electron and ion “multi-band structures” (2 or more bands at a given instance) seen in Double-Star TC1 PEACE and HIA data, mainly recorded in the equatorial plane of the inner magnetosphere (L < 15). The first two studies of this thesis present results of statistical surveys analysing distributions of electron and ion multi-bands and the conditions required for their formation. We find that these features are likely to be during times of quiet geomagnetic activity following a substorm. Band populations originate in the tail plasma sheet and lower energy bands (W ≈ 100’s eV - few keV) are observed as cold dense plasma sheet populations drift towards the inner magnetosphere. The three latter studies of this thesis focuses on using a simple particle drift model to try and illustrate whether drifts alone could create electron and ion multi-bands structures. We test drift in quiet time steady state conditions, drift after a substorm and drift in a steady state magnetosphere + diurnal electric field and show that multi-bands can be created in a number of ways for both electrons and ions.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Investigations of charged particle dynamics in the inner magnetosphere
Event: UCL (University College London)
Open access status: An open access version is available from UCL Discovery
Language: English
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/10039049
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