THE ASSOCIATION OF VISIBLE AURORAL FORMS WITH RADAR ECHOES

Abstract

A peak in 48.2-Mc/sec echo occurrence is observed at Saskatoon corresponding in time to the period of breakup of quiet arcs into active rayed structures. This is also the time of most frequent occurrence of characteristic "curl" forms in the aurora. If, as Gartlein suggests, the "curl" forms are formed by instabilities in a sheet beam then the primary particles are positively charged.