Event overview on December 3, 2011. (a, b) The GPS TEC maps at 7:15 UT and 8:45 UT, respectively. The ESR location is indicated by a pink radar symbol above Svalbard. (b) The high density plasma moved poleward toward the Svalbard archipelago and it is annotated by a black circle and a black arrow. (c) The total magnetic field (Bt), By and Bz component of IMF from the OMNI dataset. (d–g) The electron density (Ne), electron temperature (Te), ion temperature (Ti), and line of sight ion velocity (Vi) as measured by the ESR 42 m antenna at Longyearbyen. The vertical dashed blue line delimits the prenoon and postnoon sectors.