Effects of solar X‐ray flares in the E region ionosphere of Mars: First model results

Abstract

[1] We have used radio occultation data obtained from Mars Global Surveyor (MGS) at high latitudes (65.3 -65.6 N, 69.3 -69.6 N and 76.4 -77.5 N) to study the effects of X-ray flares and CMEs on Total Electron Content (TEC) in the E region of the Martian ionosphere in response to solar events that occurred on 29 and 31 May 2003 and on 17 January and 13 May 2005. Modeling of flare induced solar X-ray fluxes, ion production rates, electron densities and TEC are carried out, in each case based on GOES data. The estimated TEC values are compared with the in situ MGS observations. It is found that solar flare caused enhancements in the TEC of Mars by a factor of $5. Also, a 3D kinetic solar wind model (Hakamada-Akasofu-Fry Version 2/HAFv.2) is used to predict the arrivals of CME shocks at Mars associated with the flare event of May 2005. These predicted shock arrivals were associated with in situ enhancements in TEC by a factor of $2.

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

“…There is a reasonable agreement between measured and estimated IEC during the flare times, considering that the measurement of the IEC was available only during the decay phase of the flares. It should be noted that our estimated IEC values are most consistent with the previous calculated values of Haider et al [] at the flare time. However, a small difference in both calculations at other UTs is not surprising because their atmospheric conditions are not the same.…”

“…In addition to the radio occultation experiment, the MEX also carried the Mars Advanced Radar for the Subsurface and Ionosphere Sounding (MARSIS) experiment that measured electron density profiles above the F peak. There are no measurements in the D region ionosphere of Mars [ Haider et al , ].…”

“…They reported that the E ‐peak electron density can exceed that of the F ‐peak during intense solar flares. Haider et al [] modeled the effects of solar X‐ray flares measured by GOES 12 in the E region ionosphere of Mars during the periods 29 May to 3 June 2003, 15–20 January 2005, and 12–18 May 2005. They investigated ionospheric responses to solar X‐ray flares and CME that occurred within these intervals.…”

Observations and Modeling of the Mars Low‐Altitude Ionospheric Response to the 10 September 2017 X‐Class Solar Flare

“…In addition, electron impact ionization (EII) from photoelectrons becomes more important below the main (M2) peak (Withers, 2009). Simulating EII can be achieved by employing either an electron transport model (e.g., Fox & Dalgarno, 1979) or a wavelength-dependent yield function to represent Geophysical Research Letters 10.1029/2018GL078524 multiple ion-electron pairs being created by a single photon (e.g., Bougher et al, 2001;Fallows et al, 2015a;Haider et al, 2012;Lollo et al, 2012;Mendillo et al, 2006). Solar EUV and X-ray fluxes vary strongly with solar activity.…”

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

“…The elastic and inelastic cross sections of CO 2 , N 2 , O 2 , O, CO, and NO are adopted from theoretical results [cf. Joshipura et al ., ; Haider et al ., ]. By and large, these cross sections were found to be in good agreement at all energies with other numerous investigations and may bring an uncertainty about 10% as against the usual experimental uncertainties of 10–15% [cf.…”