Public Abstract

DE-SC0020989: Electron Energization During Magnetic Reconnection and Island Coalescence in High-S Laboratory Plasma

Award Status: Active

Institution: Board of Regents of the University of Wisconsin System, operating as University of Wisconsin-Madison, Madison, WI
UEI: LCLSJAGTNZQ7
DUNS: 161202122

Most Recent Award Date: 08/19/2024
Number of Support Periods: 4
PM: Podder, Nirmol

Current Budget Period: 09/01/2024 - 08/31/2025
Current Project Period: 09/01/2024 - 08/31/2027
PI: Egedal, Jan

Supplement Budget Period: N/A

Public Abstract

Determining the mechanisms for electron energization is a fundamental problem in plasma physics. For example, in astrophysical applications energetic electrons are responsible for a large fraction of the emitted electromagnetic radiation, yielding a window into the dynamics of astrophysical objects. This adds to the importance of understanding the underling plasma physics that governs the production and evolution of energetic electron populations. Several processes can have a significant impact on electron energization in space plasma, including electron energization at shocks and during magnetic reconnection. In the present proposal we will experimentally explore electron energization through magnetic reconnection and related magnetic island coalescence in the Terrestrial Reconnection Experiment (TREX). Several models have been proposed for electron energization during magnetic reconnection. For example, a Fermi heating model where electrons are energized at large scale during the coalescence of magnetic islands. The proposed research will use the recently enhanced capabilities of the TREX configuration to address magnetic reconnection and electron energization under conditions relevant to space and astrophysical plasma. TREX now operates at sufficiently high Lundquist number, S ~ 10⁵, that electron-ion collisions become sufficiently infrequent that non-Maxwellian features remain in the electron distribution. For a systematic study of electron heating during island coalescence, the relative currents in the drive coils will be manipulated to seed magnetic islands in a controlled manner. As such, TREX will be the first experiment to study island coalescence during controlled and repeatable conditions. The successful research will experimentally confirm theoretical models for electron heating during magnetic reconnection. The results will thus help to establish the physics basis for the modeling reconnection in space plasma. Increasingly important to emerging technologies utilizing spaceborne hardware, the gained physics understanding will also be beneficial to the ongoing efforts of improving our prediction capabilities of space weather.

Determining the mechanisms for electron energization is a fundamental problem in plasma physics. For example, in astrophysical applications energetic electrons are responsible for a large fraction of the emitted electromagnetic radiation, yielding a window into the dynamics of astrophysical objects. This adds to the importance of understanding the underling plasma physics that governs the production and evolution of energetic electron populations. Several processes can have a significant impact on electron energization in space plasma, including electron energization at shocks and during magnetic reconnection. In the present proposal we will experimentally explore electron energization through magnetic reconnection and related magnetic island coalescence in the Terrestrial Reconnection Experiment (TREX). Several models have been proposed for electron energization during magnetic reconnection. For example, a Fermi heating model where electrons are energized at large scale during the coalescence of magnetic islands. The proposed research will use the recently enhanced capabilities of the TREX configuration to address magnetic reconnection and electron energization under conditions relevant to space and astrophysical plasma. TREX now operates at sufficiently high Lundquist number, S ~ 10⁵, that electron-ion collisions become sufficiently infrequent that non-Maxwellian features remain in the electron distribution. For a systematic study of electron heating during island coalescence, the relative currents in the drive coils will be manipulated to seed magnetic islands in a controlled manner. As such, TREX will be the first experiment to study island coalescence during controlled and repeatable conditions. The successful research will experimentally confirm theoretical models for electron heating during magnetic reconnection. The results will thus help to establish the physics basis for the modeling reconnection in space plasma. Increasingly important to emerging technologies utilizing spaceborne hardware, the gained physics understanding will also be beneficial to the ongoing efforts of improving our prediction capabilities of space weather.