Radial Diffusion Driven by Spatially Localized ULF Waves in the Earth's Magnetosphere

Fuente: arXiv
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Autores principales: Osmane, Adnane, Sandhu, Jasmine, Elsden, Tom, Allanson, Oliver, Turc, Lucile
Formato: Preprint
Publicado: 2024
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author Osmane, Adnane
Sandhu, Jasmine
Elsden, Tom
Allanson, Oliver
Turc, Lucile
author_facet Osmane, Adnane
Sandhu, Jasmine
Elsden, Tom
Allanson, Oliver
Turc, Lucile
contents Ultra-Low Frequency (ULF) waves are critical drivers of particle acceleration and loss in the Earth's magnetosphere. While statistical models of ULF-induced radial transport have traditionally assumed that the waves are uniformly distributed across magnetic local time (MLT), decades of observational evidence show significant MLT localization of ULF waves in the Earth's magnetosphere. This study presents, for the first time, a quasi-linear radial diffusion coefficient accounting for localized ULF waves. We demonstrate that even though quasi-linear radial diffusion is averaged over drift orbits, MLT localization significantly alters the efficiency of particle transport. Our results reveal that when ULF waves cover more than 30\% of the MLT, the radial diffusion efficiency is comparable to that of uniform wave distributions. However, when ULF waves are confined within 10\% of the drift orbit, the diffusion coefficient is enhanced by 10 to 25\%, indicating that narrowly localized ULF waves are efficient drivers of radial transport.
format Preprint
id arxiv_https___arxiv_org_abs_2409_12649
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Radial Diffusion Driven by Spatially Localized ULF Waves in the Earth's Magnetosphere
Osmane, Adnane
Sandhu, Jasmine
Elsden, Tom
Allanson, Oliver
Turc, Lucile
Space Physics
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
Plasma Physics
Ultra-Low Frequency (ULF) waves are critical drivers of particle acceleration and loss in the Earth's magnetosphere. While statistical models of ULF-induced radial transport have traditionally assumed that the waves are uniformly distributed across magnetic local time (MLT), decades of observational evidence show significant MLT localization of ULF waves in the Earth's magnetosphere. This study presents, for the first time, a quasi-linear radial diffusion coefficient accounting for localized ULF waves. We demonstrate that even though quasi-linear radial diffusion is averaged over drift orbits, MLT localization significantly alters the efficiency of particle transport. Our results reveal that when ULF waves cover more than 30\% of the MLT, the radial diffusion efficiency is comparable to that of uniform wave distributions. However, when ULF waves are confined within 10\% of the drift orbit, the diffusion coefficient is enhanced by 10 to 25\%, indicating that narrowly localized ULF waves are efficient drivers of radial transport.
title Radial Diffusion Driven by Spatially Localized ULF Waves in the Earth's Magnetosphere
topic Space Physics
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
Plasma Physics
url https://arxiv.org/abs/2409.12649