MESSENGER Observations of Planetary Ion Enhancements at Mercury's Northern Magnetospheric Cusp During Flux Transfer Event Showers

Journal
Date Issued
2022
Author(s)
Weijie Sun
•
James A. Slavin
•
•
Ryan M. Dewey
•
Stefano Orsini
•
Xianzhe Jia
•
Jim M. Raines
•
Stefano Livi
•
Jamie M. Jasinski
•
Suiyan Fu
•
Jiutong Zhao
•
Qiu-Gang Zong
•
Yoshifumi Saito
•
Changkun Li
DOI
Abstract
At Mercury, several processes can release ions and neutrals out of the planet's surface. Here we present enhancements of dayside planetary ions in the solar wind entry layer during flux transfer event (FTE) "showers" near Mercury's northern magnetospheric cusp. The FTE showers correspond to the intervals of intense magnetopause reconnection of Mercury's magnetosphere, which form a solar wind entry layer equatorward of the magnetospheric cusps. In this entry layer, solar wind ions are accelerated and move downward (i.e. planetward) toward the cusps, which sputter upward-moving planetary ions within 1 minute. The precipitation rate is enhanced by an order of magnitude during FTE showers and the neutral density of the exosphere can vary by >10% due to this FTE-driven sputtering. These in situ observations of enhanced planetary ions in the entry layer likely correspond to an escape channel of Mercury's planetary ions, and the large-scale variations of the exosphere observed on minute-timescales by Earth observatories. Comprehensive, future multi-point measurements made by BepiColombo will greatly enhance our understanding of the processes contributing to Mercury's dynamic exosphere and magnetosphere.
Volume
127
Issue
4
Uri
Url
Issn Identifier
2169-9380
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

Sun_etal_JGR SP2022.pdf

Description
PDF editoriale
Size

3.7 MB

Format

Adobe PDF

Checksum (MD5)

6754c41a42522108536312e659778d8a