Are Morning Side Microinjections A Result of Dipolarizations?

Abstract:

MMS has observed several microinjections (Fennell et al., 2016; Sarafopoulos, 2002) in the-midnight to morning sectors of the inner magnetosphere. The character of the morning side microinjections is different from the more numerous dusk-side ones. In particular, they don’t occur in large clusters lasting for 1 to a few hours as is often the case for dusk-side events. The angular distributions of the electrons in the morning microinjections are predominantly peaked perpendicular to the magnetic field whereas the dusk-side events are peaked in the field line direction. We discuss in detail two morning side events to show some of these features. The events observed by MMS/FEEPS occurred in the 4.5-5 MLT region. Nearly simultaneously, THEMIS-D observed dipolarization front associated electron injections near midnight Preliminary analysis of the microinjection electron energy-time dispersions observed by MMS/FEEPS indicates they are consistent with having drifted from close to the THEMIS-D local time region. We examine both data sets to answer the question of whether they are connected such that the near midnight dipolarizations could be the source of the microinjections observed near dawn by MMS.

Fennell, J. F., et al., (2016), Microinjections observed by MMS FEEPS in the dusk to midnight region, Geophys. Res. Lett., 43, doi:10.1029/2016GL069207.
Sarafopoulos, D. V., (2002), Dispersive and repetitive Pc5 mode microinjections in the inner magnetosphere, Geophys. Res. Lett., 29, doi:10.1029/2001GL014067.