Global Imaging of the Earth Tail Reconfiguration With ENA Detectors: Insights From Global Models

Several substorm onset mechanisms and corresponding tail reconfigurations have been hotly debated by the community over last half century. Despite this extended debate there no consensus within the community regarding the physical process or processes triggering substorm onset. One of the main issues in reaching scientific closure for substorm onset is that it is difficult to observe both the global and mesoscale tail dynamics from in-situ spacecraft or ground-based instrumentation. Here, we present the results of global ENA simulations from the BATSRUS MHD model coupled with the ring current CIMI model to investigate the dynamics of the mesoscale tail structures around substorm onset. We investigate the response in ENAs from 1 keV to 50 keV, from several viewing geometries, to identify the time and spatial resolution and sensitivity required to observe substorm-related tail structures, namely; current sheet thinning, dipolarization and formation of bursty bulk flows, substorm particle injections. The results from our study will be critical for the future development of ENA imaging instrumentation and missions.