Abstract

BARDHAN, ANANNA; SHARMA, DINESH KUMAR; KUMAR, SARVESH  and  RAI, JAGDISH. Variation of the O⁺ ion density during low and high solar activity as measured by the SR0SS-C2 satellite. Atmósfera [online]. 2014, vol.27, n.3, pp.227-237. ISSN 0187-6236.

The O⁺ ion density measured by the SROSS-C2 satellite during solar minima (year 1995, F_10.7 = 77) and maxima (year 2000, F_10.7 = 181) has been analyzed for studying diurnal, seasonal, latitudinal and geomagnetic variations. The study region covers an area encompassed between 5-35° N latitude and 65-95° E longitude over India at a ~500 km altitude (F2 region). The year 2000 shows significant enhancement in the annual average of O⁺ ion density and attainment of post sunset secondary enhancement compared to 1995. Attributed to photoionization, daytime shows a maximum ionization compared to nigttime. However, attainment of post sunset secondary maxima is attributed to the strong pre-reversal enhancement in the vertical E x B drift. The effect of geomagnetic activity Kp through the E x B drift dynamic movement on O⁺ ion density distribution studies indicates periodicities of seven and nine days in 1995 and 2000, respectively, and polynomial dependency of the O⁺ ion density on geomagnetic activity Kp. Further on, stratification of the O⁺ ion density according to latitude (5-35° N) indicates high density in mid-latitudes (12-24° N) compared to high and low latitudes, except in the winter of 1995, which shows a distinct trend (i.e., density decreases with increasing latitude).

Keywords : F2 region; O⁺ ion density; pre-reversal enhancement; E x B drift: geomagnetic activity (Kp); solar minima and maxima.

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