Fig. 2: Schematic of the magnetopause crossing and whistler-mode waves (Event 1).

MMS crossed the magnetopause southward of the reconnection site from the terrestrial magnetosphere to the magnetosheath. The interval with whistler mode waves focused as Event 1 (around 15:59:19 UT on 25 December 2016) was close to the magnetosheath-side separatrix (blue curve) of the magnetopause reconnection that occurred northward of MMS.