Electron Heating and Associated Electrostatic Waves in Magnetic Flux Rope Embedded Within Super‐Alfvén Plasma Flow

• Published in: Geophysical research letters Vol. 50; no. 18
• Main Authors: Chen, Z. Z., Wang, J., Liu, C. M., Yu, J., He, Z. G., Liu, N. G., Cui, J., Cao, J. B.
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.09.2023; Wiley
• Subjects: Acceleration; Broadband; broadband electrostatic waves; Drift; Electron beams; Electron heating; Electrons; Electrostatic properties; Electrostatic waves; Heating; lower‐hybrid drift waves; Magnetic flux; magnetic flux ropes; Magnetic reconnection; magnetosphere; Particle interactions; Plasma waves; Plasmas (physics); Ropes; Thermalization (energy absorption); Turbulence; Wave propagation
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2023GL104994

Magnetic flux ropes (MFRs) are significant regions for the production of energetic electrons in space and astrophysical plasmas. However, the research on electron heating and acceleration driven by turbulence in MFRs is still quite rare. Utilizing in‐situ measurements from MMS satellite, we study electron heating and associated electrostatic waves in an ion‐scale MFR within terrestrial super‐Alfvén plasma flow. Lower‐hybrid drift waves, generated locally in this MFR, can contribute to the perpendicular heating through their electrostatic potential accelerating electrons. The parallel heating is attributed to antiparallel propagating electron beams. These beams excite the broadband electrostatic waves that can interact with electrons and thermalize electrons. Our study promotes understanding of electron energization driven by plasma waves and wave‐particle interaction in MFRs. Plain Language Summary Magnetic flux ropes (MFRs) are ubiquitous magnetic structures existing in space and astrophysical plasmas. They are produced by magnetic reconnection, and can in turn trigger small‐scale reconnection and modulate reconnection process. In addition, they are widely used to explain electron heating and acceleration, which is a long‐standing problem in space and astrophysical plasmas. Thus, they receive significant attention nowadays. However, there has been still lack of research on electron heating and acceleration driven by turbulence in MFRs. In our study, we find perpendicular electron heating is partly attributed to lower‐hybrid drift waves and parallel electron heating is closely related to antiparallel propagating electron beams, which excites strong broadband electrostatic waves that can result in thermalization of electrons. Key Points Electron heating is detected inside an ion‐scale magnetic flux rope Lower‐hybrid drift waves can contribute to the perpendicular heating through their electrostatic potential accelerating electrons The parallel heating is caused by electron beams, which excite the broadband electrostatic waves that can thermalize electrons