A Statistical Study of Magnetopause Boundary Layer Energetic Electron Enhancements Using MMS
Presentation Type
Talk
Presenter Format
In Person Meeting Talk
Topic
Dayside Science
Start Date
10-5-2022 11:30 AM
Abstract
We took a survey of low-latitude boundary layer crossings by the Magnetospheric Multiscale (MMS) mission. Out of 250 total crossings, about half showed enhancements of high-energy (>30 keV) electrons in the FEEPS sensor and a little less than half of those energetic electron events had whistler-mode waves present. Energetic electron enhancements were more likely to be present at magnetic local times closer to noon and at distances of less than about 20 Earth radii, but there was seemingly no correlation with magnetic latitude. For almost all of these events, the pitch angles of the FEEPS electrons were peaked at 90o or isotropic, not field-aligned. Almost all events had an elevated velocity moment within a few minutes of the whistler waves, suggesting reconnection nearby, but only a few showed reconnection jets with a sudden spike and immediate drop within a few minutes. Overall, energetic electron enhancements are a fairly common occurrence and are likely associated with reconnection. Using test particle simulations, we found that phase trapping from non-linear whistler waves (typically invoked in radiation belt acceleration) could be a viable method of accelerating these electrons within the boundary layer.
A Statistical Study of Magnetopause Boundary Layer Energetic Electron Enhancements Using MMS
We took a survey of low-latitude boundary layer crossings by the Magnetospheric Multiscale (MMS) mission. Out of 250 total crossings, about half showed enhancements of high-energy (>30 keV) electrons in the FEEPS sensor and a little less than half of those energetic electron events had whistler-mode waves present. Energetic electron enhancements were more likely to be present at magnetic local times closer to noon and at distances of less than about 20 Earth radii, but there was seemingly no correlation with magnetic latitude. For almost all of these events, the pitch angles of the FEEPS electrons were peaked at 90o or isotropic, not field-aligned. Almost all events had an elevated velocity moment within a few minutes of the whistler waves, suggesting reconnection nearby, but only a few showed reconnection jets with a sudden spike and immediate drop within a few minutes. Overall, energetic electron enhancements are a fairly common occurrence and are likely associated with reconnection. Using test particle simulations, we found that phase trapping from non-linear whistler waves (typically invoked in radiation belt acceleration) could be a viable method of accelerating these electrons within the boundary layer.
