Kumar, Ashok ; Lodhi, Neelesh K. ; Mahajan, K. K. (2007) Near-terminator Martian ionosphere during sunspot cycle 23 from Mars Global Surveyor radio science measurements Indian Journal of Radio and Space Physics, 36 (6). pp. 457-465. ISSN 0367-8393
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Abstract
Radio Science experiment on the Mars Global Surveyor (MGS) has measured a large number of electron density pro-files in the near-terminator Martian ionosphere, from December 1998 to March 2005, thus covering rising, maximum and declining phase of sunspot cycle 23. More than a dozen data sets, EDS 1 to EDS 13, are now available at the public website and these sets contain profiles numbering from a few tens in some sets to several hundreds in others. On any one day, several profiles were measured at a constant solar zenith angle (x) but at different longitudes. However, x varied considerably during each data set and in this paper about 2000 profiles have been analysed to study the height (hm) and density (Nm) of the primary peak as a function of solar zenith angle. A significant decrease of Nm is seen with increasing x, but hm starts increas-ing at x above 80° only. To examine how close the Martian primary peak is to an ideal Chapman layer, values of exponent, k and sub-solar peak density, No in the equation Nm = No (cos x)k were obtained by using the largest number of profiles em-ployed ever before. A value of 0.45 for the exponent k deduced is somewhat smaller than the value of 0.5 expected for an ideal Chapman layer. Value of No was found to be 1.75 × 1011 m-3. Anomalous features in the Mars ionosphere seen in the earlier MGS data are found to be present in the latest data also.
Item Type: | Article |
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Source: | Copyright of this article belongs to National Institute of Science Communication and Information Resources. |
Keywords: | Martian Ionosphere; Mars Global Surveyor (MGS); Chapman Layer; Electron Density Profiles; Solar Zenith Angle |
ID Code: | 75864 |
Deposited On: | 20 Jun 2012 14:02 |
Last Modified: | 18 May 2016 19:44 |
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