Modeling the dawn/dusk asymmetry of field line resonances
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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.
Wright , A N , Elsden , T & Takahashi , K 2018 , ' Modeling the dawn/dusk asymmetry of field line resonances ' , Journal of Geophysical Research: Space Physics , vol. 123 , no. 8 , pp. 6443-6456 . https://doi.org/10.1029/2018JA025638
Journal of Geophysical Research: Space Physics
©2018. American Geophysical Union. All Rights Reserved. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at: https://doi.org/10.1029/2018JA025638
DescriptionANW was partially funded by STFC (ST/N000609/1) and the Leverhulme Trust (RPG-2016-071). TE was funded by the Leverhulme Trust (RPG-2016-071). KT was supported by NASA grant NNX17AD34G.
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