Fig. 1
From: MMS observations of electron scale magnetic cavity embedded in proton scale magnetic cavity
MMS observations of an ESMC coupled with a proton scale magnetic cavity. Panels a–c show MMS1 observations of turbulent magnetic fields, proton energy–time spectrogram as well as the total magnetic field (Bt), and proton pitch angle distribution (PAD) in 30 s from 14:59:20UT to 14:59:50 UT on 23 October 2015. A depression region of Bt is marked with two dashed vertical lines across the four panels. The Bt observed by MMS1 is over-plotted as a black curve in panel b. The magenta curves in panel c represent a local loss cone, derived from the variation of Bt. The ESMC discussed in this paper is the first one of two sudden dips of Bt near 14:59:34 UT in panel b, the observations of which are detailed in panels d–h, with a very short time scale (0.6 s). Panel d shows Bt observed by four MMS spacecraft, and panels e–h show electron PADs observed by MMS2, 3, 1, and 4, respectively. In panels f–h the corresponding local loss cones are over-plotted as magenta curves. Spacecraft positions are labeled at the bottom of the figure
