Studies of electron and ion temperatures at 500 km altitude during sunrise using Indian SROSS C2 satellite

Abstract

Solar dependence of electron and ion temperatures ( T e and T i) in the ionosphere is studied using RPA data onboard SROSS C2 at an altitude of ∼500 km and 77°E longitude during early morning hours (04:00–07:00 LT) for three solar activities: solar minimum, moderate and maximum during winter, summer and equinox months in 10°S–20°N geomagnetic latitude. In winter the morning overshoot phenomenon is observed around 06:00 LT ( T e enhances to ∼4000 K) during low-solar activity and to T e ∼ 3800 K, during higher solar activity. In summer, it is observed around 05:30 LT, but the rate of T e enhancement is higher during moderate solar activity (∼2700 K/hr) than the low-solar activity (∼1700 K/hr). During equinox, this phenomenon is delayed and is observed around 06:00 LT (∼4200 K) during all three activities. In winter, the T i shows an enhancement (∼2300 from ∼700 K) around 06:00 LT during low-solar activity but during other activities, it raise smoothly with the progress of the morning. In summer, T i increases at a rate of 260 K/hr during low and moderate activities and with half the rate (∼130 K/hr) during high-solar activity. And in equinox months, the T i is lower during high-solar activity than in low-solar activity.