HORIZONTAL MOVEMENTS OF AURORA

Abstract

Measurements on the drifts of auroral forms at three stations to the south of the auroral zone in West-Central Canada failed to show evidence of a motion due to the earth's rotation relative to fixed excitation patterns in space. The distribution and the magnitude of the speed of auroral structures parallel and normal to the geomagnetic meridians are substantially the same as for non-luminous ionic irregularities observed by radio methods. The speed of an auroral arc or band parallel to the geomagnetic meridian is apparently constant. Speeds increase with geomagnetic activity, particularly in an east-west direction. There is no definite indication of a reversal of the east-west motions close to local midnight. Speeds and directions show no characteristic variations with the time of night.