The effect of magnetic substorms on near-ground atmospheric current

摘要: Abstract. Ionosphere-magnetosphere disturbances at high latitudes, e.g. magnetic substorms, are accompanied by energetic particle precipitation and strong variations of the ionospheric electric fields currents. These might reasonably be expected to modify local atmospheric circuit. We have analysed air-earth vertical currents (AECs) measured a long wire antenna Esrange, northern Sweden during 35 geomagnetic substorms. Using superposed epoch analysis we compare current 3 h before after time X-component minimum with those for corresponding times on days without After elimination average daily variation can conclude that effect substorms AEC is small but distinguishable. It speculated increases observed about 2 prior minimum, due enhancement field. During subsequent substorm recovery phase, difference between "substorm" "quiet" decreases. The amplitude this estimated less than 50% diurnal in same interval. statistical significance result was confirmed using Van der Waerden X-test. This method further used show its fluctuations increase late expansion early phases Key words: Ionosphere (electric currents) · Magnetospheric physics (storms substorms) Meteorology dynamics (atmospheric electricity)