Journal Article

Modulation of Energetic Electron Precipitation Driven by Three Types of Whistler Mode Waves

Qin, Murong, Capannolo, Luisa, Ma, Qianli, Zhang, Xiao‐Jia, Shen, Xiao‐Chen, Angelopoulos, Vassilis, Huang, Sheng, Artemyev, Anton V., Li, Wen

2023

Overview

Precipitation into the Earth's atmosphere due to pitch angle scattering by plasma waves has been recognized as one of the major loss mechanisms for energetic electrons. In this study, we quantitatively evaluate their roles in precipitating electrons during a conjunction event with modulated electron precipitation observed at low altitudes by Electron Loss and Fields INvestigation and three types of whistler mode waves (hiss, plume hiss, and chorus) measured near the equator by Time History of Events and Macroscale Interactions during Substorms. Electron precipitation was observed from ∼50 keV to <1 MeV with a spatial modulation, suggested by a good correlation between L shell‐sorted precipitation fluxes and wave intensities. A quasi‐linear analysis supports the observed energy range of precipitation and the ratio of precipitating‐to‐trapped flux. Our findings reveal that the modulated energetic electron precipitation is driven by hiss, plume hiss, and chorus waves. Plain Language Summary Energetic electrons precipitated from the inner magnetosphere into the upper atmosphere can form diffuse and discrete aurora and modulate the ionospheric conductance. One of the major drivers of electron precipitation is wave‐particle interaction with whistler mode waves. In this study, we use the Electron Loss and Fields INvestigation CubeSats to measure electron precipitation at low altitudes and the Time History of Events and Macroscale Interactions during Substorms to provide wave and plasma measurements near the magnetic equator in the conjugate locations. We find that the electron precipitation rate is highly correlated to the whistler mode wave intensity near the equator. Through a quasi‐linear analysis, we demonstrate that the modulation of electron precipitation is driven by whistler mode hiss, plume hiss, and chorus waves that occur in an extensive region of the Earth's magnetosphere. Key Points Modulated electron precipitation from tens to hundreds of keV over L shells of 4–9 is observed by Electron Loss and Fields INvestigation at low altitudes A good correlation is observed between the spatial variations of electron precipitation and wave intensities of hiss, plume hiss, and chorus Quasi‐linear modeling based on the observed wave and plasma parameters reproduced the observed electron precipitation

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Altitude / Atmosphere / Auroras / chorus / Chorus waves / Cubesat / Earth / Earth magnetosphere / Electron precipitation / Electrons / Equator / Fields / Hiss / ionosphere / Linear analysis / Low altitude / Magnetic equator / magnetosphere / Modulation / Particle interactions / Pitch (inclination) / Plasma waves / Precipitation / Upper atmosphere / Waves / whistler / Whistlers