DRIFT SPIKES : THE IONOSPHERIC SIGNATURE OF LARGE POLEWARD DIRECTED ELECTRIC FIELDS AT SUBAURORAL LATITUDES

• Main Authors: R. S. UNWIN, C. H. CUMMACK
• Format: Report
• Language: English
• Published: Physics and Engineering Laboratory, Geophysical Observatory 1980
• Subjects: Campbell Island; New Zealand; The Spike; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1075; http://id.nii.ac.jp/1291/00001075/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1075&item_no=1&attribute_id=18&file_no=1

A VHF doppler auroral radar operating in the south of New Zealand since early 1978 has quite frequently observed long persisting echoes with large doppler shifts over a limited range interval. These are confined to dark hours, are primarily in the premidnight sector, lie between 58°S and 62°S invariant, and closely follow the onset of the expansive phase of substorms. There seems little doubt that they are the ionospheric signature of the large poleward directed electric fields observed in the F region by AE-C, S3-2 and OGO-6,although no direct confirmation has yet been possible. We have called these phenomena "drift spikes". The characteristics of the auroral radar data are described and related to magnetic and ionosonde data from Campbell Island at 60.1°S invariant. It is shown that drift spikes occur in the F region trough on the equatorward edge of the easterly electrojet, which itself decays as the spike develops. In some degree the spike may reflect the behaviour of the westerly electrojet at high latitudes.