The Canadian CASSIOPE small satellite mission: The enhanced polar outflow probe and Cascade technology demonstration payloads

Plasma sheet electron precipitation is critical in magnetosphere‐ionosphere coupling and has long been attributed to electron scattering by whistler‐mode and electron cyclotron harmonic waves. Recent observations have revealed that time domain structures (TDSs) that appear as broadband electrostatic fluctuations may also scatter plasma sheet electrons. However, there has been no observational evidence of TDS scattering electrons into the ionosphere. This study presents potential evidence from conjugate observations between the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission and the low‐altitude Enhanced Polar Outflow Probe (e‐POP) spacecraft. During the five events presented, THEMIS observed intense electron injections accompanied by TDSs, while e‐POP captured precipitation of plasma sheet electrons with energies ∼100–325 eV over a broad pitch angle range. The observed TDSs can efficiently scatter these electrons exceeding the strong diffusion limit. Our results suggest that TDSs may contribute to plasma sheet electron scattering around times of injections.

Section: Introductionmentioning

confidence: 82%

Potential Evidence of Low‐Energy Electron Scattering and Ionospheric Precipitation by Time Domain Structures

Shen

Artemyev

Zhang

et al. 2020

“…The experimental evidence of the connection between TDSs and electron precipitation was presented by Shen et al. (2020), based on the observations of Time History of Events and Macroscale Interactions during Substorms (THEMIS) (Angelopoulos, 2008) and the ionospheric e‐POP (Enhanced Polar Outflow Probe) (Yau & James, 2015; Yau et al., 2015) missions.…”

Section: Introductionmentioning

confidence: 99%

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

Khazanov

Glocer

Chu

2021

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

“…The first experimental evidence of the connection between TDSs and ionospheric electron precipitation was recently presented by Shen et al. (2020), based on conjugate observations of Time History of Events and Macroscale Interactions during Substorms (THEMIS) (Angelopoulos, 2008) and the low‐altitude Enhanced Polar Outflow Probe (e‐POP) (Yau & James, 2015; Yau et al., 2015) missions. Motivated by Shen et al.…”

Section: Introductionmentioning

confidence: 99%

Magnetosphere‐Ionosphere Coupling of Precipitated Electrons in Diffuse Aurora Driven by Time Domain Structures

Khazanov

Shen

Vasko

et al. 2021

The diffuse aurora precipitations provide more than 70% of the energy flux from the magnetosphere to the ionosphere (e.g., Newell et al., 2009). Based on the rigorous FAST spacecraft analysis provided by Dombeck et al. (2018), this percentage of the energy coming from the diffuse aurora is potentially a large overstatement. It is, nonetheless, still substantial and likely in the range of ∼30%-70%. These precipitations modify the ionosphere conductance, affecting thereby the convection electric field in the magnetosphere (e.g., Hardy et al., 1989). Therefore, the understanding of the sources and modeling of the fluxes of diffuse aurora precipitations represent the substantial interest for modeling the magnetosphere-ionosphere coupling (e.g., Yu et al., 2016).It is widely accepted that the diffuse aurora is primarily produced by magnetospheric electrons scattered into the loss cone by wave-particle resonant interaction processes, either driven by electron-cyclotron harmonic (ECH) waves at radial distances larger than ∼8 Earth radii (