spase://NASA/DisplayData/UCLA/Global-MHD-code/mS1-Vx/PT10S

This movie of the GSM X component of plasma flow velocity is on the original, not interpolated grid. Flow directions are displayed on a reduced grid 1/7 the size of the original. Vectors saturate at an equatorial speed of 300 km/s to avoid clutter. Red and yellow colors show earthward flows while blue colors identify tailward flow. Contours of Vx = 250 km/s are denoted by heavy black lines. Inside these contours abs(Vx) reaches values of 500 km/s or more. White lines are contours of plasma pressure. Heavy black and white lines at >10 Re pre-midnight depict the location of THEMIS spacecraft. A dashed black semi-circle defines synchronous orbit. The Earth is a green half-circular patch. The first image in this movie at 04:00 UT is the start of the growth phase of a substorm with onset at 04:44 UT. This image demonstrated the validity of one of the key points of this paper. Reconnection and fast flows are continuously present throughout the entire substorm. At this time, keograms from ground station in the pre-midnight sector show no auroral activity poleward of the growth phase arcs except for RANK where aurora was present in the northeastern sky, which did not contribute to its keogram. This location projects close to the moon. The location of reconnection sites is evident from bifurcation in the high-speed flow with red earthward and blue tailward. At this moment, there are six earthward fast flow channels. Our arbitrary constraint on channel area eliminated the two small channels from further consideration. Activation of the movie reveals that the two fast flow channels in this image turn towards the flanks just outside the apogee of the THEMIS spacecraft. By the substorm onset at 04:44 UT, various x-lines coalesce into a single 55 Re long x-line with a high-speed flow channel engulfing the THEMIS spacecraft. By 04:55 UT, this channels breaks up into three separate channels