The wedge-like ion spectral structures in the inner magnetosphere

Abstract

Energetic ions from the plasma sheet will be freshly injected into the inner magnetosphere during geomagnetic activities, and exhibit some spectral features named after the shapes of energy bands in the energy-time spectrograms such as the “nose-like” structure,“trunk-like” structure, and ion spectral gap. Using the ion observations from Van Allen Probes launched in 2012, my work revealed the existence of a new ion structures, which is the wedge-like structure of O+, He+, and H+ ions in the inner magnetosphere. The wedge-like structures have the energy range of eV-keV and can penetrate into deep regions (even L<2). Via the conjugate observations of different spacecraft and simulations, we found that the wedge-like and nose-like spectral signatures are merely the manifestations of one single structure along different spacecraft trajectories, which are associated with the intermittent substorm injections in the nightside magnetosphere. The comparisons between observations and simulations of the wedge-like structures can help find out the shortcomings of the empirical convection electric models and improve them.