Statistical Study of the Energetic Electron Microinjections at the High-latitude Magnetosphere
Presentation Type
Talk
Presenter Format
In Person Meeting Talk
Topic
Dayside Science
Start Date
10-5-2022 3:45 PM
Abstract
Understanding the formation of the seed population for the energetic electrons trapped within the Earth’s Van Allen radiation belts has been under debate for decades. The magnetic reconnection in the Earth’s magnetotail during the substorms is considered to be the main process considered to accelerate the electrons to the tens to hundreds of keV. These electrons are then further injected toward the radiation belts, where they get further accelerated to relativistic energies. Recently, it has been suggested that another source could come from the dayside diamagnetic cavities where electrons and ions can be locally accelerated to hundreds of keV. It has been shown that the acceleration mechanism within cavities can create a strong temperature anisotropy which leads to drift mirror instability and injection of electrons parallel and anti-parallel to magnetic field potentially accessing inner magnetosphere. As a first part of this study, this presentation focuses on the statistical study of the energetic electron microinjections and their relation to solar wind, IMF conditions and local plasma/field parameters. We find total of 165 hours of dispersionless energy-time microinjections in the high latitude pre-dusk sector and they coincidence with the magnetic field variations in the Ultra Low Frequency (ULF) range, often with similar frequencies. Many of these ULF fluctuations show features consistent with mirror mode waves, and can potentially be one of the sources for microinjections due to wave particle interactions.
Statistical Study of the Energetic Electron Microinjections at the High-latitude Magnetosphere
Understanding the formation of the seed population for the energetic electrons trapped within the Earth’s Van Allen radiation belts has been under debate for decades. The magnetic reconnection in the Earth’s magnetotail during the substorms is considered to be the main process considered to accelerate the electrons to the tens to hundreds of keV. These electrons are then further injected toward the radiation belts, where they get further accelerated to relativistic energies. Recently, it has been suggested that another source could come from the dayside diamagnetic cavities where electrons and ions can be locally accelerated to hundreds of keV. It has been shown that the acceleration mechanism within cavities can create a strong temperature anisotropy which leads to drift mirror instability and injection of electrons parallel and anti-parallel to magnetic field potentially accessing inner magnetosphere. As a first part of this study, this presentation focuses on the statistical study of the energetic electron microinjections and their relation to solar wind, IMF conditions and local plasma/field parameters. We find total of 165 hours of dispersionless energy-time microinjections in the high latitude pre-dusk sector and they coincidence with the magnetic field variations in the Ultra Low Frequency (ULF) range, often with similar frequencies. Many of these ULF fluctuations show features consistent with mirror mode waves, and can potentially be one of the sources for microinjections due to wave particle interactions.
