GEOTAIL (red) and ACE (black) solar wind conditions. The data from GEOTAIL in the near-Earth solar wind are advanced by 7 min, whereas those from ACE, located approximately 230 R
E upstream in the solar wind, are delayed by 47 min. The (a)
Y-, and (c)
Z-components of the IMF in the geocentric solar magnetospheric coordinate, (d) the solar wind proton density, (e) the flow speed, and (f) the dynamic pressure are plotted. The two dotted lines indicate the time when Auroras B and C appeared in the dayside ionosphere.