Jichun Zhang, Ph.D.,
Space Science Center, University of New Hampshire
Understanding ion injection into the inner magnetosphere is a critical part of understanding the physical dynamics of the Earth’s magnetosphere. Ions in the inner magnetosphere interact with the magnetic and electric fields, which can affect the radiation belt environment and its variability. In addition, they play a key role in controlling wave activity, which affects both particle acceleration and loss in this region. Nose structures, often observed by spacecraft in the Earth’s inner magnetosphere, are important observational signatures of ion injection from the outer magnetosphere. These structures, named after “nose-like” features in the ion energy-time spectrograms, are a key indicator of the degree to which ions are able to penetrate into the inner magnetosphere. Quantitative understanding of how these structures are generated will provide insight into the dynamic processes operating in the inner magnetosphere, including time-dependent particle injections and electric fields. The observed features of nose structures also constitute a test ground for inner-magnetospheric theories and modeling. In the talk, I will present our recent results from the combination of in-situ measurements from Cluster and Van Allen Probes (also called Radiation Belts Storm Probes, i.e., RBSP) with numerical simulations from the Rice Convection Model (RCM). Several fundamental questions are addressed in the presentation: 1) How do ions access the inner magnetosphere, and what affects the ion transport into the inner magnetosphere? 2) What factors control ion injection and the formation of the ion spectral features? 3) How well do RCM, the state-of-the-art inner-magnetospheric model, reproduce ion dynamics in the inner magnetosphere?
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