SM23B-2544
Observations of the Evolution of Ion Outflow During a Sawtooth Event
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Eric J Lund1,2, Niloufar Nowrouzi1,3, Lynn M Kistler1,3, Xia Cai4 and Harald U Frey5, (1)University of New Hampshire Main Campus, Space Science Center, Durham, NH, United States, (2)College Brook Scientific, Durham, NH, United States, (3)University of New Hampshire, Physics Department, Durham, NH, United States, (4)Science Systems and Applications, Inc. Hampton, Hampton, VA, United States, (5)University of California Berkeley, Berkeley, CA, United States
Abstract:
Sawtooth oscillations are one of several convection modes known to exist in the magnetosphere. Recent simulations have suggested that O$^+$ ions transported from the high-latitude ionosphere to the magnetotail can drive sawtooth events. We present observational case studies of sawtooth events using data from FAST near the noon-midnight meridional plane, Cluster in the magnetotail, GOES and LANL energetic particle sensors at geosynchronous orbit, and ACE solar wind data to investigate the evolution of ion outflow during sawtooth events and the question of whether O$^+$ outflow from one tooth helps to drive subsequent teeth. We find that oxygen enters the tail from the lobes after each tooth onset, the oxygen fraction in the magnetotail often increases after a tooth onset, and that the oxygen fraction of outflowing ions increases after a tooth event both in the cusp and on the nightside. However, a significant amount of low energy oxygen ($\lesssim 1$~keV) can end up in the dayside inner magnetosphere.
