Distinctive features of internally driven magnetotail reconnection. Issue 7 (14th April 2017) - Sitnov, M. I.
Abstract: Onset of reconnection in a tail‐like equilibrium with a finite B z magnetic field component is studied using 3‐D explicit particle‐in‐cell simulations. Due to a region of a tailward B z gradient the onset develops spontaneously as the magnetic flux release instability with dominant earthward ion flows. The instability drives the change of magnetic field topology internally, without any external forcing. The distinctive features of this regime are: previously unreported Hall magnetic field patterns; energy conversion near the dipolarization front prior to the X line formation; asymmetry of the energy conversion, plasma heating, and anisotropy relative to the X line, with regions of ion and electron heating out of phase both along and across the tail. These features distinguish the internally driven reconnection regime from similar processes in antiparallel magnetic field configurations as well as interchange and externally driven magnetotail reconnection regimes and can be used to identify the different regimes in upcoming Magnetospheric Multiscale (MMS) mission tail season observations. Key Points: Magnetotail reconnection can be driven internally due to magnetic flux release instability New patterns of Hall magnetic field, plasma heating, anisotropy, and agyrotropy are demonstrated in this regime Energy dissipation at the dipolarization front precedes the topology change