Variability of the interplanetary magnetic field as a driver of electromagnetic induction in Mercury’s interior
File(s)
Accepted version
Author(s)
Zomerdijk-Russell, Sophia
Masters, Adam
Heyner, Daniel
Type
Journal Article
Abstract
Mercury’s magnetosphere is a unique and dynamic system, primarily due to the proximity of the planet to the Sun and its small size. Interactions between solar wind and embedded Interplanetary Magnetic Field (IMF) and the dayside Hermean magnetosphere drive an electric current on the system’s magnetopause boundary. So far, electromagnetic induction due to magnetopause motion in response to changing external pressure has been used to constrain Mercury’s iron core size. Here we assess the impact a changing IMF direction has on the Hermean magnetopause currents, and the resulting inducing magnetic field. Observations made by MESSENGER during dayside magnetopause boundary crossings in the first ‘hot season’, are used to demonstrate the importance of the IMF direction to Mercury’s magnetopause currents. Our 16 boundary crossings show that introduction of external IMFs change the magnetopause current direction by 10° to 100°, compared to the case where only the internal planetary field is considered. Analytical modelling was used to fill in the bigger picture and suggests for an east-west reversal of the IMF, typical of the heliospheric current
3 sheet sweeping over Mercury’s magnetosphere, the inducing field at Mercury’s surface caused by the resulting magnetopause current dynamics is on the order of 30% of the global planetary field. These results suggest that IMF variability alone has an appreciable effect on Mercury’s magnetopause current and generates a significant inducing magnetic field around the planet. The arrival of the BepiColombo mission will allow this response to be further explored as a method of probing Mercury’s interior.
3 sheet sweeping over Mercury’s magnetosphere, the inducing field at Mercury’s surface caused by the resulting magnetopause current dynamics is on the order of 30% of the global planetary field. These results suggest that IMF variability alone has an appreciable effect on Mercury’s magnetopause current and generates a significant inducing magnetic field around the planet. The arrival of the BepiColombo mission will allow this response to be further explored as a method of probing Mercury’s interior.
Date Issued
2021-10
Date Acceptance
2021-09-13
Citation
Journal of Geophysical Research: Space Physics, 2021, 126 (10), pp.1-15
ISSN
2169-9380
Publisher
American Geophysical Union
Start Page
1
End Page
15
Journal / Book Title
Journal of Geophysical Research: Space Physics
Volume
126
Issue
10
Copyright Statement
© 2021. American Geophysical Union. All Rights Reserved. This is the accepted version of the following article: Zomerdijk-Russell, S., Masters, A., & Heyner, D. (2021). Variability of the interplanetary magnetic field as a driver of electromagnetic induction in Mercury's interior. Journal of Geophysical Research: Space Physics, 126, e2021JA029664, which has been published in final form at https://doi.org/10.1029/2021JA029664
Sponsor
The Royal Society
Science and Technology Facilities Council
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JA029664
Grant Number
UF150547
ST/S006230/1
Subjects
0201 Astronomical and Space Sciences
0401 Atmospheric Sciences
Publication Status
Published
Date Publish Online
2021-09-23