Unique latitudinal shape of ion upper transition height (HT) surface during deep solar minimum (2008–2009). Issue 2 (16th February 2015)

• Record Type: Journal Article
• Authors: Tulasi Ram, S.; Heelis, R.; Gowtam, V. Sai; Ajith, K. K.; Su, S.‐Y.
• Is Part Of: Journal of geophysical research. Volume 120:Issue 2(2015:Feb.)
• Page Start: 1419
• Page End: 1427
• Publication Date: 2015-02-16
• Subjects: Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2014JA020647
• Languages: English
• ISSNs: 2169-9380

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The ionospheric upper transition height (<italic>H_T</italic>) is found to increase dramatically by ~100 km from 2008–2009 to 2010 only for a marginal increase in solar activity (<italic>F</italic>_10.7) by 11.76 solar flux units. The latitudinal variation of <italic>H_T</italic> surface during 2008–2009 period exhibits a local minimum at equatorial latitudes and increase at low latitudes. Further, the <italic>H_T</italic> at equatorial latitudes exhibits slower rate of increase than at low latitudes. These interesting features are new and different from those reported in literature. A quick loss of O⁺ and increase in H⁺ ions are observed around ~550 to 650 km indicating that the charge exchange reaction is responsible for the slower rate of increase and lowered <italic>H_T</italic> at equatorial latitudes. These new aspects of <italic>H_T</italic> are more conspicuously observed during this deep solar minimum period where the resonant charge exchange reaction is taking place at altitudes as low as ~550 km.</p> </abstract>