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Modeling the Dawn/Dusk Asymmetry of Field Line Resonances

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journal contribution
posted on 08.04.2020, 11:16 by Andrew N Wright, Tom Elsden, Kazue Takahashi
Field line resonances (FLRs) are observed to occur preferentially and have larger amplitudes at dawn compared to dusk. We present simulations of FLR excitation in a magnetospheric waveguide that can reproduce this behavior. Crucially, our equilibrium is asymmetric about noon. Even when this system is driven in a symmetric fashion about noon, the fast waves that are established in the magnetosphere develop asymmetries—as do the FLRs they excite. Fast mode ray trajectories are employed to show that the asymmetry evolves due to refraction. Preferential FLR excitation at dawn is further reinforced by calculating the Resonance Map. This shows that the Resonant Zone at dawn coincides with a large-amplitude coherent fast mode driver, which is not the case at dusk. These factors result in FLRs having a larger amplitude at dawn compared to dusk.

Funding

Funding Information STFC. Grant Number: ST/N000609/1 Leverhulme Trust. Grant Number: RPG-2016-071 NASA. Grant Number: NNX17AD34G

History

Citation

Wright, A. N., Elsden, T., & Takahashi, K. ( 2018). Modeling the dawn/dusk asymmetry of field line resonances. Journal of Geophysical Research: Space Physics, 123, 6443– 6456. https://doi.org/10.1029/2018JA025638

Version

VoR (Version of Record)

Published in

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS

Volume

123

Issue

8

Pagination

6443 - 6456 (14)

Publisher

AMER GEOPHYSICAL UNION

issn

2169-9380

eissn

2169-9402

Acceptance date

28/06/2018

Copyright date

2018

Available date

05/07/2018

Publisher version

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JA025638

Language

English