Control of the East‐West Component of the Interplanetary Magnetic Field on the Occurrence of Magnetic Substorms
Abstract
We study the effects of the east‐west (y) component of the interplanetary magnetic field (IMF) on the occurrence of substorms by analyzing 16,743 magnetic substorm events identified with the SuperMAG SML index from 1995 to 2016. It is found, surprisingly, that substorm occurrence rates depend highly on the sign of IMF By, with, on average, ~1/3 more substorms for IMF By > 0 than for IMF By By > 0 conditions. A superposed epoch analysis of the IMF indicates that the average IMF By prior to onset is positive but becomes less positive ~15 min prior to the onset, indicating that the release of the stress associated with a clockwise twisted magnetotail may be an important onset trigger. We conjecture that an asymmetry in the dayside merging efficiency may be the cause.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 10, 2020
- Source ID
- 10.1029/2020gl087406
Entities
People
- Elizabeth Mitchell
- Kan Liou
- Thomas Sotirelis
Organizations
- Air Force Office of Scientific Research
- Johns Hopkins University
- National Science Foundation