Nightside Plasmaspheric Plume‐To‐Core Migration of Whistler‐Mode Hiss Waves. Issue 16 (23rd August 2022)

• Record Type: Journal Article
• Authors: Wu, Zhiyong; Su, Zhenpeng; Goldstein, Jerry; Liu, Nigang; He, Zhaoguo; Zheng, Huinan; Wang, Yuming
• Is Part Of: Geophysical research letters. Volume 49:Issue 16(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-23
• Subjects: whistler‐mode hiss -- plasmaspheric plume -- cross‐correlation -- hiss generation -- wave‐particle interaction -- ray‐tracing simulation; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2022GL100306
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Whistler‐mode hiss waves play an important role in the radiation belt electron depletion. Whether the hiss waves with significant differences in amplitude and propagation direction within the plasmaspheric core and plume are related to each other remains unclear. We here show that the plasmaspheric plume facilitates the energy conversion from energetic electrons to hiss waves and then guides hiss waves into the plasmaspheric core. Three ground and space missions captured the initial formation and subsequent rotation of the plasmaspheric plume in the noon‐dusk‐midnight sector following a strong substorm. The observed hiss waves in the nightside plasmaspheric plume and core propagated oppositely but highly correlated with each other at a time lag of 4–10 s. The linear instability of energetic electrons in the plasmaspheric plume qualitatively explains the frequency‐dependence of hiss waves, and the ray‐tracing modeling reproduces the propagation direction and timing of hiss waves. Plain Language Summary: In the Earth's inner magnetosphere, plasmaspheric hiss is a natural band of whistler‐mode waves spanning from tens of hertz to several kilohertz. It was so named because it is confined to the dense plasmasphere and sounds like white noise when played through a loudspeaker. It is well known that both the plasmaspheric core and plume sustain hiss waves and these waves differ significantly in both amplitude and propagation direction. However, whether these hiss waves of different regions are related or not remains unclear. On the basis of data from three ground and space missions and detailed modeling, we show that the plasmaspheric plume facilitates the energy conversion from energetic electrons to hiss waves and then guides hiss waves into the plasmaspheric core. This depiction of the plume's role could be generalized toward other plasmaspheric structures extending outward such as the plasmaspheric bulge, fingers, and crenulations. Key Points: Three ground and space missions observed the formation and evolution of plasmaspheric plume following a strong substorm Hiss waves propagating oppositely in the nightside plasmaspheric plume and core correlated highly with each other at a time lag of 4–10 s Numerical modeling supports that the plasmaspheric plume allows hiss waves to grow and then migrate to the plasmaspheric core