Electron‐Scale Front of Magnetic Pile‐Up Region in Reconnection Exhaust

Abstract

Magnetic reconnection, a ubiquitous and fundamental energy conversion process in space and astrophysical plasmas, is responsible for explosive phenomena such as magnetospheric substorms, solar flares and coronal mass ejections (Angelopoulos et al., 2008;Cao et al., 2013;P. F. Chen, 2011). It can efficiently convert the stored magnetic energy to particle's energy in the form of outward fast flows, particle heating and acceleration as the magnetic field lines break and reconnect (

Electron Rolling‐Pin Distributions Preceding Dipolarization Fronts

“…To further diagnose the electron transport in these events, we investigate Phase space density (PSD) (omni‐directional PSD) of suprathermal electrons before (corresponding to the observed rolling‐distributions) and after the DFs, as shown in Figure 3. As can be seen, electron PSDs in these events can basically be fitted with power‐law distributions whose indexes are close to the range reported in previous studies (e.g., Chen et al., 2023; Liu et al., 2017). For event 1, power law index for rolling‐pin electrons prior to the front is ∼5.1, close to that (5.0) for cigar electrons behind the front.…”

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

“…Z. Chen et al, 2022bChen et al, , 2023Khotyaintsev et al, 2019Khotyaintsev et al, , 2020. As the wave number increases, the oblique propagating waves can be excited.…”

“…Multiple waves lie on the dispersion surface (Figure 4j), such as the highly nonlinear solitary structures (e.g., DLs and ESW) and more periodic broadband electrostatic E ∥ waves (Z. Z. Chen et al., 2022b, 2023; Khotyaintsev et al., 2019, 2020). As the wave number increases, the oblique propagating waves can be excited.…”

Magnetic Hump Associated with Electron Vortex at Dipolarization Front

“…Such electron-scale finger-like/rippled structures are capable of accelerating electrons to a higher energy than that accelerated by typical smooth DFs (Bai et al 2022). In addition to such an electron-scale substructure at DFs, a recent study has confirmed the existence of an electron-scale front, at which a strong electron jet and structured electric field drive intense energy conversion, while ions cannot respond (Chen et al 2023). Even at DFs with a typical thickness in the order of ion inertial length, electron jets play crucial roles in energy conversion, as demonstrated by recent studies that show that strong energy conversion is primarily attributed to currents driven by electron jets (e.g., Liu et al 2018;Zhou et al 2019) rather than ions, as suggested in other studies (e.g., Khotyaintsev et al 2017).…”

“…They are suggested to play crucial roles in the transportation of mass, flux, and energy in the Earth's magnetosphere (Runov et al 2009;Liu et al 2014;Lui 2015;Wang et al 2020) as they can propagate over long distances with the velocity of hundreds of kilometers per second (Runov et al 2009;Ge et al 2011) in the Earth's magnetotail. The generation of DFs is attributed to several mechanisms, including magnetic reconnection (Sitnov et al 2009;Fu et al 2013;Chen et al 2023), flux rope erosion (Lu et al 2015), spontaneous formation (Sitnov et al 2013), flow braking (Panov et al 2010;Birn et al 2011), and interchange/ ballooning instabilities (Pritchett & Coroniti 2010;Lu et al 2013).…”