Please use this identifier to cite or link to this item: http://nopr.niscair.res.in/handle/123456789/14034
Title: Behaviour of the low-latitude ionosphere-plasmasphere system at long deep solar minimum
Authors: Balan, N
Chen, C Y
Liu, J Y
Bailey, G J
Keywords: Electron temperature, Equatorial ionization anomaly
Ionosphere-plasmasphere system, Ion temperature
Plasma flux, Vertical ion drift velocity
Wind velocity
Issue Date: Apr-2012
Publisher: NISCAIR-CSIR, India
Abstract: The behaviour of the low-latitude ionosphere-plasmasphere system during the long deep solar minimum between solar cycles 23 and 24 is presented using the physics based model SUPIM and FORMOSAT-3/COSMIC satellite data. Using the vertical ion drift velocity measured by C/NOFS satellite, and neutral densities and wind velocities obtained from MSIS and HWM, SUPIM calculates the electron and ion (O<sup>+</sup>, H<sup>+</sup>, He<sup>+</sup>, N<sub>2</sub><sup>+</sup>, O<sub>2</sub><sup>+</sup>, and NO<sup>+</sup>) densities and temperatures and plasma fluxes within ±40<sup>o</sup> magnetic latitudes and 150-2000 km heights for Indian longitudes at equinox (F10.7 = 68, Ap = 4). FORMOSAT-3 measures the corresponding electron density up to 600 km height. The data and model show the ionosphere contracting to a thin layer during the long deep solar minimum. During daytime, the ionosphere has a half-width of only about 250 km over the equator and 150 km at EIA crests with a peak density of about 10<sup>6</sup> cm<sup>-3</sup> and O<sup>+</sup>/H<sup>+</sup> transition height at around 750 km. At night, the ionosphere reduces to a cold thin layer of half-width less than about 150 km at the crests with a peak density of about 10<sup>5</sup> cm<sup>-3</sup>, and transition height about 500 km where the ion densities reduce to about 10<sup>4</sup> cm<sup>-3</sup>. Plasma density in the plasmasphere (above transition height) remains nearly constant at about 10<sup>4</sup> cm<sup>-3</sup> during both day and night, and decreases only very slowly with height. However, the temperatures increase rapidly at sunrise at all heights to reach about 2500 K (electron) and 2250 K (ion) at 0800 hrs LT at 2000 km height (at EIA crests), which decrease by a maximum of only 250 K until sunset. After sunset, both electrons and ions cool rapidly until about midnight and then decrease slowly to nearly constant temperatures at all heights to about 650 K prior to sunrise. SUPIM predictions and FORMOSAT-3 data agree also with C/NOFS and CHAMP satellite observations.
Description: 89-97
URI: http://hdl.handle.net/123456789/14034
ISSN: 0975-105X (Online); 0367-8393 (Print)
Appears in Collections:IJRSP Vol.41(2) [April 2012]

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