On the Formation of Wedge-Like Ion Spectral Structures in the Nightside Inner Magnetosphere

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Keywords
Abstract
Recent observations in the nightside inner magnetosphere have identified a series of wedge-like spectral structures in the energy-time spectrograms of oxygen, helium, and hydrogen ion fluxes. Although the shapes and distributions of these structures have been characterized by case and statistical studies, their formation mechanism remains unclear. Here we utilize a particle tracing model to reproduce the wedge-like structures successively observed by the twin Van Allen Probes. The model suggests that these structures originate from intermittent substorm injection, and it is the accessibility region of these injected ions that determines their shapes. This mechanism is similar to the formation of another kind of structures, the inner magnetospheric nose-like structures, except that the wedge-like structures are separated from the tail population by the discontinuation of ion injections. This scenario is also supported by the distribution statistics of wedge-like structures, which provides new insights into the dynamics of the magnetotail-inner magnetosphere coupled system.
Notes
Year of Publication
2020
Journal
Journal of Geophysical Research: Space Physics
Volume
125
Number
Number of Pages
e2020JA028420
Date Published
11/2020
URL
https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020JA028420
DOI
https://doi.org/10.1029/2020JA028420