Response of low-latitude ionosphere of the Indian region during the supergeomagnetic storm of 31 March 2001

Abstract

[1] The study explores the response of ion composition (H+ and O+ ion) and ion temperature at the F2 region altitude during the intense geomagnetic storm of 31 March 2001 by using retarding potential analyzer onboard SROSS-C2 satellite data over the low-latitude region. The simultaneous enhancement of H+ ion and ion temperature along with depletion of O+ ion concentration is observed at the altitude of about 350 km during the beginning of storm recovery phase. These results are unique of their kind and attributed to the energetic particle (H+/H atoms) originating from ring current and the consequent charge exchange reaction. In addition, the ionosonde observations show the short-term positive storm effect during the main phase and beginning of recovery phase (RP) over the low-mid latitude station, Delhi. The results clearly show that such effect is due to the passage of storm-induced traveling atmospheric disturbances. The dominance of storm-induced disturbance circulation is also observed during the second day of RP in terms of enhanced peak density heights. The rise in height due to storm-induced meridional wind is effectively seen in the nighttime ionosphere and is not associated with any considerable variation in F2 region critical frequency.