Fig. 7

The evolution of equatorial plasma bubbles measured by ICON and F7/C2 IVM around Taiwan on 18 October 2020. a Shows the ICON and F7/C2 orbits while the magnetic equator is shown with by black dashed line. The red and black points denote E- and F-region sunset terminator locations corresponding to the respective orbits, where the line segments through these points indicate the alignment of the terminator. The black and red curves indicate the measured ion density and calculated background density from b ICON IVM, c F7/C2E1 IVM, d F7/C2E2 IVM e F7/C2E3 IVM (~ 2100 LT), and f F7/C2E3 (~ 2200 LT), respectively. The blue, magenta and cyan dots indicate the west and east edges of EPB2 and the west edge of EPB3, respectively