Comprehensive Observations of Substorm‐Enhanced Plasmaspheric Hiss Generation, Propagation, and Dissipation

• Published in: Geophysical research letters Vol. 47; no. 2
• Main Authors: Liu, Nigang, Su, Zhenpeng, Gao, Zhonglei, Zheng, Huinan, Wang, Yuming, Wang, Shui, Miyoshi, Yoshizumi, Shinohara, Iku, Kasahara, Yoshiya, Tsuchiya, Fuminori, Kumamoto, Atsushi, Matsuda, Shoya, Shoji, Masafumi, Mitani, Takefumi, Takashima, Takeshi, Kazama, Yoichi, Wang, Bo‐Jhou, Wang, Shiang‐Yu, Jun, Chae‐Woo, Chang, Tzu‐Fang, Tam, Sunny W. Y., Kasahara, Satoshi, Yokota, Shoichiro, Keika, Kunihiro, Hori, Tomoaki, Matsuoka, Ayako
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.01.2020
• Subjects: Activation; Cyclotron resonance; Earth; Electromagnetic radiation; GOES satellites; Hiss; Hot electrons; Magnetospheres; Plasmasphere; plasmaspheric hiss; Radiation; radiation belt; Radiation belts; Shape recognition; Space missions; Spacecraft; Spacecraft survivability; Spreading; Survival; wave dissipation; wave generation; Wave power; wave propagation
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2019GL086040

Plasmaspheric hiss is an important whistler‐mode emission shaping the Van Allen radiation belt environment. How the plasmaspheric hiss waves are generated, propagate, and dissipate remains under intense debate. With the five spacecraft of Van Allen Probes, Exploration of energization and Radiation in Geospace (Arase), and Geostationary Operational Environmental Satellites missions at widely spaced locations, we present here the first comprehensive observations of hiss waves growing from the substorm‐injected electron instability, spreading within the plasmasphere, and dissipating over a large spatial scale. During substorms, hot electrons were injected energy‐dispersively into the plasmasphere near the dawnside and, probably through a combination of linear and nonlinear cyclotron resonances, generated whistler‐mode waves with globally drifting frequencies. These waves were able to propagate from the dawnside to the noonside, with the frequency‐drifting feature retained. Approximately 5 hr of magnetic local time away from the source region in the dayside sector, the wave power was dissipated to e−4 of its original level. Plain Language Summary A noisy band of electromagnetic waves with frequencies ranging from tens of hertz to several kilohertz in the Earth's plasmasphere is termed plasmaspheric hiss. These waves are recognized to shape the Van Allen radiation belt environment and then affect the spacecraft survivability and lifetime. How the plasmaspheric hiss waves are generated, propagate, and dissipate has been a fundamental unanswered question since their discovery. With three space missions scattered in the inner magnetosphere, we present here the first comprehensive observations of hiss waves growing from the substorm‐injected electron instability, spreading within the plasmasphere, and dissipating over a large spatial scale. These findings have significant implications for the modeling of the plasmaspheric hiss waves and the Van Allen radiation belt dynamics. Key Points Near the dawnside, energy‐dispersively injected electrons generated plasmaspheric hiss with globally drifting frequencies The frequency drift feature allowed tracing the plasmaspheric hiss propagation from the dawnside to the noonside The dayside plasmaspheric hiss dissipated away roughly within a magnetic local time span of 5 hr