Fig. 1

Kaguya observations from 04:10 to 04:30 UT on April 2, 2008, including an ESW event in the wake boundary studied by Hashimoto et al. (2010). From the top, a frequency–time spectrogram of electric field from X-channel of WFC-H; b frequency–time spectrogram of electric field from Y-channel; c angles between the local magnetic field and X-channel and Y-channel antennas; d magnetic fields in the SSE coordinate system; e magnetic connection to the lunar surface estimated by a linear extrapolation of the magnetic field at the spacecraft (brown: forward connection (not applicable), green: backward connection, black: magnetically detached (not applicable)); f electron energy–time spectrogram from ESA-S2; g electron energy–time spectrogram from ESA-S1; h pitch-angle time spectrogram from ESA-S1 and ESA-S2; i ion energy–time spectrogram from IMA; j altitude of Kaguya from the average lunar surface; k solar zenith angle. Latitude and longitude at the footprint of the spacecraft in the ME coordinate system are presented at the bottom. The vertical dotted lines mark the times when electron pitch-angle distributions in Fig. 1 were taken