The Precipitated Electrons in the Region of Diffuse Aurora Driven by Ionosphere‐Thermosphere Collisional Processes

Abstract

Electron precipitation in the region of the diffuse aurora provides a noticeable amount of energy to the Ionosphere-Thermosphere (IT) system (e.g., Newell et al., 2009) and is the subject of debate in the recent experimental studies of this phenomena (Dombeck et al., 2018). It is generally assumed that either whistler mode chorus waves or Electrostatic electron Cyclotron Harmonic (ECH) waves are mostly responsible for the initiation of such electron precipitation to begin with, depending on the spatial location. Whistler mode chorus waves are more effective at geocentric distances r

Impact of Soft Electron Precipitation on the Thermospheric Neutral Mass Density During Geomagnetic Storms: GITM Simulations

“…However, it has been found that the Maxwellian energy spectrum tends to underestimate the incident soft (0.1–1 keV) electrons and the difference of the 0.1 keV electrons can be up to 2–3 orders of magnitude (e.g., McGranaghan, Knipp, Matsuo, et al., 2015; McGranaghan, Knipp, Solomon, Fang, 2015; McIntosh & Anderson, 2014; Wing et al., 2019). Although modeling efforts have been made to incorporate additional types of energy spectra different from a Maxwellian energy spectrum in recently developed electron precipitation models (e.g., McGranaghan et al., 2016; Newell et al., 2009, 2014), soft electron precipitation may still be inaccurately represented (Khazanov et al., 2021; Wing et al., 2019). Since soft electron precipitation is an important ionization source in the F‐region ionosphere, the conductivity and Joule heating at F‐region altitudes may not be correctly estimated when the Maxwellian energy spectrum is used in GCMs (e.g., McGranaghan et al., 2016; Rees, 1989).…”

Dayside Low Energy Electron Precipitation Driven by Hiss Waves in the Presence of Ionospheric Photoelectrons

“…Compared to the previous studies by Khazanov at al. (2017); Khazanov, Glocer, and Chu (2021); Khazanov, Shen, et al (2021), a STET code running configuration in the tilted dipole magnetic field is presented for the first time. Such an approach allows to take care of different realistic illumination conditions in the Northern and Southern Hemispheres that is an important element in the proper calculation of photoelectron fluxes.…”

“…It solves gyro-average kinetic equation for the suprathermal electrons (SE) for the energies above 1 eV and include relativistic effects (Khazanov, 2010). This kinetic equation for the SE can be presented as (Khazanov, Shen, et al, 2021, Khazanov, Glocer, & Chu, 2021)…”

“…Following Khazanov, Shen, et al. (2021) and Khazanov, Glocer, and Chu (2021), we fit the energy spectrum of trapped electron fluxes at 1–30 keV energies using a Maxwellian‐type distribution function (blue), with the fitting coefficients shown in Figures 1e and 1f. The fitted electron flux distribution is used in the STET code.…”

“…During these processes they lose their energy and degrade toward 100 eV energies. They also experience elastic collision with the neutral particles and backscatter toward the magnetosphere and the conjugate ionospheric region (Khazanov, Shen, et al., 2021, Khazanov, Glocer, & Chu, 2021).…”