Electron Heating by Debye-Scale Turbulence in Guide-Field Reconnection

Abstract

We report electrostatic Debye-scale turbulence developing within the diffusion region of asymmetric magnetopause reconnection with moderate guide field using observations by the Magnetospheric Multiscale (MMS) mission. We show that Buneman waves and beam modes cause efficient and fast thermalization of the reconnection electron jet by irreversible phase mixing, during which the jet kinetic energy is transferred into thermal energy. Our results show that the reconnection diffusion region in the presence of a moderate guide field is highly turbulent, and that electrostatic turbulence plays an important role in electron heating. arXiv:1908.09724v1 [physics.space-ph]

Collisionless Magnetic Reconnection and Waves: Progress Review

“…Such distributions can be unstable to both quasi-parallel and oblique whistlers at the same time. This is supported by reported events where the quasi-parallel and oblique whistlers co-exist in the separatrix regions on the magnetospheric side of the magnetopause (Zhou et al, 2018;Khotyaintsev et al, 2019). Figure 7A summarizes different types of VDFs leading to whistler generation in the vicinity of the X-line.…”

“…Eventually, the electron two-stream instability would take over, leading to higher phase speeds and continuing to thermalize the beam. This scenario was recently confirmed in an event study of guide-field reconnection at the dayside magnetopause by MMS (Khotyaintsev et al, 2019); it was shown that the electron reconnection jet was gradually thermalized due to the waveparticle interaction of broadband electrostatic turbulence.…”

“…Such waves have oblique wave normal angles of ∼45 • , have large amplitude electric fields with polarization close to linear, i.e., E ⊥ and E || of similar amplitude (Wilder et al, 2017;Khotyaintsev et al, 2019). Solving a kinetic dispersion solver using the observed electron distributions suggests whistler generation by electron beams is viable for both magnetotail and magnetopause conditions (Khotyaintsev et al, 2019;Ren et al, 2019).…”

AME: A Cross-Scale Constellation of CubeSats to Explore Magnetic Reconnection in the Solar–Terrestrial Relation

“…Turbulence and coherent structures universally exist in space plasmas. Kinetic-scale turbulence is strongly coupled to dissipative processes such as magnetic reconnection and shocks [46][47][48]. One form of turbulence in space plasmas is flow eddies.…”

Electron Mixing and Isotropization in the Exhaust of Asymmetric Magnetic Reconnection With a Guide Field

“…At the Earth's magnetopause, magnetic reconnection is generally asymmetric, and often with a guide field (e.g., Burch & Phan, ; Chen et al, ; Genestreti et al, ; Khotyaintsev et al, ; Webster et al, ; Zhou et al, ). The superposition of the positive/negative bipolar‐type Hall magnetic field and the guide field can enhance/reduce the out‐of‐plane magnetic field in the two different exhausts.…”