No abstract

It is formed by the gradient and curvature drift of particles, together with the diamagnetic behavior of charged particles in the inner magnetosphere (e.g., Friedel et al., 2001;Longmire, 1963;Rossi & Olbert, 1970;Yue et al., 2017). Energetic ions such as protons and oxygen (O + ) ions are thought to be the main carriers of the ring current (e.g., Krimigis et al., 1985;Yue et al., 2018). Protons contribute most to the ring current during geomagnetic quiet times, while O + ions could be the major specie of the ring current during active times (Daglis

Electron phase-space holes, sometimes abbreviated to electron holes, are usually believed to be a kind of electrostatic solitary waves with positive electric potentials. In the traditional Bernstein-Green-Kruskal (BGK) scenario (Bernstein et al., 1957), low-energy electrons are trapped by the positive potential of electron holes, and the positive potential is supported by the lower phase-space density of these trapped electrons than the ambient population, which in turn results in a local positive charge. This one-dimensional, unmagnetized model can be further extended to explain the one-dimensional structures aligned with magnetic field lines in magnetized plasmas, which is the usual case in space observations (see review by Hutchinson, 2017). Laboratory experiments