Properties of a cusp diamagnetic cavity boundary

Abstract

Abstract. While crossing through the high-altitude dayside cusp on 29 September 1978 and again on 30 October 1978, the ISEE-1 spacecraft observed enhanced energetic particle flux and a depressed and turbulent magnetic field, the signature characteristics of a cusp diamagnetic cavity. As ISEE-1 approached the cavity during each event, a boundary sounding technique was used to measure properties of an emitting boundary. Sounding over multiple energy channels reveals an energy dependent boundary with lower energy particles filling a larger cavity than higher energy particles. Relative motion of the boundary as well as boundary orientation are also measured. The two cusp events were measured at different locations and during different geomagnetic and solar wind conditions; however, they show similar results.

The Structure of the Cusp Diamagnetic Cavity and Test Particle Energization in the GAMERA Global MHD Simulation

“…A diamagnetic cavity (DMC) can form in the Earth's high latitude magnetosphere as long as large‐scale reconnection is occurring at the magnetopause such that the reconnection process forms a kink in the field resulting in a magnetic bottle geometry. When the reconnection occurs in the vicinity of the northern or southern cusp, the resulting cavities are commonly referred to as cusp DMCs (Chen et al., 1998; Lavraud et al., 2005; Nykyri, Otto, Adamson, Dougal, & Mumme, 2011; Walsh et al., 2008). A cusp DMC forms where old reconnected flux is advected away from the magnetopause x‐line toward the cusp.…”