Electric fields in the vicinity of auroral forms from motions of barium vapor releases

Abstract

In August -September, 1967, eleven barium vapor clouds were released during evening twilight between invariant magnetic latitudes of 67.3 0 to 68.1 0 from And4ya, Norway. Two flights (8 releases) occurred during moderate negative bays in H, while the third flight (3 releases) took place during a positive bay in-H. Visual auroral displays were observed in the vicinity during all flights. In the negative bay situation, barium ion cloud motions 3 were eastward, and closely parallel to auroral arc alignments. Electric fields transverse to the magnetic field with intensities of 10 to 130 my /m 3 directed southward were observed. During the positive bay event the barium clouds spanned the breakup transition region, with the two equatorwards clouds moving westward while the poleward cloud went east. Observed reversals in direction were closely correlated with magnetic variations.