Numerical simulation of the effects of meteoroid ablation and solar EUV/X‐ray radiation in the dayside ionosphere of Mars: MGS/MEX observations

Abstract

We have developed a model which produces three plasma layers simultaneously due to the impact of the meteoroids, solar X-ray (0.5-9 nm), and EUV (9-102.6 nm) radiation at altitude range 75-85 km, 100-115 km, and 135-140 km, respectively, in the dayside ionosphere of Mars. The calculated results are compared with the radio occultation measurements made by Mars Express (

Flare X‐ray photochemistry of the E region ionosphere of Mars

“…This method calculates photoionization and photoelectron impact ionization rates, photoelectron flux, ion/electron density, and IEC simultaneously at different height, time, and energy. Following Pandya and Haider [] the analytical form of the AYS method is represented by where C 0 , C 1 , and C 2 are adjustable parameters of CO 2 , N 2 , O 2 , O, and CO. These parameters were obtained by a nonlinear least squares fitting procedure [ Singhal and Green , ].…”

“…In equation the incident X‐ray photon flux is taken from Figure between wavelength range of 1–8 Å at 5 min time resolution and energy bins of 0.2 Å. The photoabsorption and photoionization cross sections of CO 2 , N 2 , O 2 , O, and CO are taken from Pandya and Haider [], who compiled it in Tables A1 and A2, respectively, from different investigators [ Torr and Torr , ; Cairns and Samson , ; Cook et al , ; Lee et al , ; McCulloh , ; Iida et al , ; Watanabe et al , ]. The photoionization rate Q ( h , χ , t ) is obtained from primary photoelectron spectrum Q ( h , χ , E , t ) by integrating it over energy E .…”

“…It is assumed that photoelectrons are ejected isotropically. We have used mixture of five gases CO 2 , N 2 , O 2 , O, and CO in the AYS model at altitude h and time t. This method has been used by us in several research problems related to electron energy degradation in planetary atmospheres Singhal et al, 1980;Singhal and Green, 1981;Haider and Singhal, 1983;Singhal and Haider, 1984;Seth et al, 2002Seth et al, , 2006Bhardwaj and Jain, 2009;Haider et al, 2010;Pandya and Haider, 2014].…”

“…This method calculates photoionization and photoelectron impact ionization rates, photoelectron flux, ion/electron density, and IEC simultaneously at different height, time, and energy. Following Pandya and Haider [2014] the analytical form of the AYS method is represented by…”

“…In equation (7) the incident X-ray photon flux is taken from Figure 1 between wavelength range of 1-8 Å at 5 min time resolution and energy bins of 0.2 Å. The photoabsorption and photoionization cross sections of CO 2 , N 2 , O 2 , O, and CO are taken from Pandya and Haider [2014], who compiled it in Tables A1 and A2, respectively, from different investigators [Torr and Torr, 1979;Cairns and Samson, 1965;Cook et al, 1966;Lee et al, 1973;McCulloh, 1973;Iida et al, 1986;Watanabe et al, 1967]. The photoionization rate Q(h, χ, t) is obtained from primary photoelectron spectrum Q(h, χ, E, t) by integrating it over energy E. The time-dependent photoionization and photoelectron impact ionization rates are calculated for six flare days on 28 March and 6 April 2001, 17 and18 March and21 April 2003, and19 February 2005 at solar zenith angles 72°, 72°, 71°, 71°, 73°, and 73°respectively.…”