SH43A-2413
Ion Bernstein waves in a magnetic reconnection region
Thursday, 17 December 2015
Poster Hall (Moscone South)
Yasuhito Narita1, Rumi Nakamura2, Wolfgang Baumjohann3, Karl-Heinz Glassmeier4, Uwe Motschmann5 and Horia Comisel5, (1)Space Research Institute, Schmiedlstr. 6 A-8042 Graz, Austria, (2)Austrian Academy of Sciences, Vienna, Austria, (3)Space Research Institute, Austrian Academy of Sciences, Graz, Austria, (4)TU Braunschweig, Institute of Geophysics and extraterrestrial Physics, Braunschweig, Germany, (5)TU Braunschweig, Institute of Theoretical Physics, Braunschweig, Germany
Abstract:
Four-dimensional energy spectra and a diagram for dispersion relations are determined for the first time in a magnetic reconnection region in the magnetotail using the four-point magnetometer data from the Cluster mission on a spatial scale of 200 km, about 0.1 ion inertial lengths. The energy spectra are anisotropic with an extension in the perpendicular direction and axially asymmetric with respect to the mean magnetic field. The dispersion diagram for the waves in the quasi-perpendicular directions in the plasma rest frame is in reasonably good agreement with the ion Bernstein waves particularly at the second harmonic of the proton gyro-frequency. Perpendicular-propagating ion Bernstein waves likely exist in an outflow region of magnetic reconnection. We discuss the causality of the Bernstein waves with magnetic reconnection with an estimate of the anomalous resistivity, and propose an observationally-driven model of turbulent magnetic reconnection.
