An MMS multicase study of magnetotail dipolarization fronts

Friday, 18 December 2015
Poster Hall (Moscone South)
Daniel Schmid1,2, Rumi Nakamura1, Ferdinand Plaschke1, Martin Volwerk1, Yasuhito Narita1, Wolfgang Baumjohann1, Werner Magnes1, David Fischer1, Roy B Torbert3,4, Christopher T Russell5, Robert J Strangeway5, Hannes Karl Leinweber5, Kenneth R Bromund6, Brian J Anderson7, Guan Le6, Mark Chutter3, James A Slavin8, Larry Kepko6, Mark Moldwin8 and Olivier Le Contel9, (1)Space Research Institute, Austrian Academy of Sciences, Graz, Austria, (2)University of Graz, NAWI, Graz, Austria, (3)University of New Hampshire, Durham, NH, United States, (4)Southwest Research Institute San Antonio, San Antonio, TX, United States, (5)University of California Los Angeles, Los Angeles, CA, United States, (6)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (7)The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States, (8)University of Michigan Ann Arbor, Ann Arbor, MI, United States, (9)Laboratoire de Physique des Plasmas, Paris, France
Dipolarization fronts (DFs) are characterized by a rapid increase in the northward magnetic field component (Bz) and play a crucial role in the energy and magnetic flux transport in the magnetotail. Multispacecraft observations of DFs in a large portion of the magnetotail by e.g. Geotail, Cluster and THEMIS have been reported for over three decades.
During the commissioning phase of MMS we are able to observe DFs at radial distances within 8 Re, which is in a more dipolarized region (well within the flow braking region). We present a statistical study of DFs observed during March-May 2015, using only magnetic field data. First results indicate that the amplitude of the found DFs is greater compared to similar events in the distant tail. Timing analysis yields that many of the DFs propagate tailward, which would suggest a rebound (bouncing) of the DF at the magnetic dipole-dominated near-Earth plasma sheet. Since MMS spacecraft are in a “string-of-pearls” configuration, further analysis is ongoing to evaluate the obtained direction from a simple timing analysis. We compare and contrast the found DFs with that from the DF-eventlist introduced in Schmid et al. [J. Geophys. Res., 2, 120 (2015)], which is based on 9 years (2001-2009) of Cluster magnetotail observations.