Storm-to-storm main phase repeatability of the local time variation of disturbed low-latitude vertical ion drifts

摘要

Penetration electric field can be very strong during magnetic storms. However, the variation of penetration electric field with local time (LT) has not been well understood. The Communication/Navigation Outage Forecasting System (C/NOFS) satellite measures the plasma drift/electric field over all local times within similar to 100min. In this paper, we present the first nearly simultaneous observations of the dependence of penetration electric field on local time. The meridional ion drift measured by C/NOFS during the main phase of five magnetic storms in 2012 is analyzed. The storm time ion drift shows a large enhancement around 1900LT, a relatively small enhancement during daytime, and a deep decrease in the postmidnight sector with a peak around 0500LT. The observed storm time variation of the meridional ion drift with local time represents the variation of the penetration electric field. The averaged ion drifts are in remarkable agreement with recent simulations.