Flux Transfer Event Showers at Mercury: Dependence on Plasma β and Magnetic Shear and Their Contribution to the Dungey Cycle

Sun, W. J., Slavin, J. A., Smith, Andy, Dewey, R. M., Poh, G. K., Jia, X., Raines, J. M., Livi, S., Saito, Y., Gershman, D. J., DiBraccio, G. A., Imber, S. M., Guo, J. P., Fu, S. Y., Zong, Q. G. and Zhao, J. T. (2020) Flux Transfer Event Showers at Mercury: Dependence on Plasma β and Magnetic Shear and Their Contribution to the Dungey Cycle. Geophysical Research Letters, 47 (21). e2020GL089784. ISSN 0094-8276

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Official URL: https://doi.org/10.1029/2020GL089784

Abstract

Mercury's flux transfer event (FTE) showers are dayside magnetopause crossings accompanied by large numbers (≥10) of magnetic flux ropes (FRs). These shower events are common, occurring during 52% (1,953/3,748) of the analyzed crossings. Shower events are observed with magnetic shear angles (θ) from 0° to 180° across the magnetopause and magnetosheath plasma β from 0.1 to 10 but are most prevalent for high θ and low plasma β. Individual FR duration correlates positively, while spacing correlates negatively, with θ and plasma β. FR flux content and core magnetic field intensity correlate negatively with plasma β, but they do not correlate with θ. During shower intervals, FRs carry 60% to 85% of the magnetic flux required to supply Mercury's Dungey cycle. The FTE showers and the large amount of magnetic flux carried by the FTE-type FRs appear quite different from observations at Earth and other planetary magnetospheres visited thus far.

Item Type: Article
Additional Information: Funding Information: MESSENGER data used in this study were available from the Planetary Data System (PDS; http://pds.jpl.nasa.gov ). The MESSENGER project was supported by the NASA Discovery Program under contracts NASW‐00002 to the Carnegie Institution of Washington and NAS5‐97271 to The Johns Hopkins University Applied Physics Laboratory. W. J. S. and J. A. S. were supported by NASA grants NNX16AJ67G and 80NSSC18K1137. A. W. S. was supported by STFC consolidated grant ST/S000240/1 and NERC grant NE/P017150/1. R. M. D. was supported by NASA's Earth and Space Science Fellowship Program (80NSSC17K0493). The magnetopause crossings along with local coordinates are available in the table named “DaysideMagnetopause_List.txt” in the supporting information .
Uncontrolled Keywords: Dungey Cycle, Flux Transfer Events, Flux Transport, Magnetic Shear Angle, Plasma Beta
Subjects: F300 Physics
F500 Astronomy
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 07 Nov 2022 10:55
Last Modified: 07 Nov 2022 11:00
URI: https://nrl.northumbria.ac.uk/id/eprint/50556

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