CONTROL ID: 1490593
TITLE: Response of the M1 Layer of the Mars Ionosphere to Solar Variability
ABSTRACT BODY: We investigate the response of the two main plasma layers of the ionosphere of Mars to changes in incident ionizing solar flux, with a focus on the highly variable secondary layer. We determine the altitude, number density, and vertical width of both layers in 5600 Mars Global Surveyor (MGS) electron density profiles, and analyze the variation in these parameters with the solar zenith angle. We also compare these parameters to changes in the incident EUV and soft X-ray solar flux as represented by the Solar Irradiance Platform (SIP) model. We find that the low-altitude, secondary layer, (M1), responds to changes in the solar flux and solar zenith angle in a manner similar to that of the primary layer of the ionosphere, (M2). One significant difference is the vertical width of the M1 layer, which increases with increasing peak electron density, whereas the width of M2 layer does not appear strongly correlated with the density of the layer.
We also use a one-dimensional photochemical model to simulate the Mars ionosphere each day during a six month stretch of MGS observations, with daily SIP irradiances as input. Both layers of the simulated electron density profiles exhibit many of the same responses to solar zenith angle and incident solar flux as seen in the MGS data. However, the simulations do not show an increase in the vertical width of the M1 layer as the peak number density increases.


CURRENT SECTION/FOCUS GROUP: SPA-Aeronomy
CURRENT SESSION: SA012. Solar System Aeronomy: Ionospheres, Thermospheres, Auroras, and Airglow
INDEX TERMS: [6225] PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS / Mars, [5435] PLANETARY SCIENCES: SOLID SURFACE PLANETS / Ionospheres, [5405] PLANETARY SCIENCES: SOLID SURFACE PLANETS / Atmospheres.
AUTHORS/INSTITUTIONS: K. Fallows, Z.R. Girazian, M.M. Matta, P. Withers, Astronomy Department, Boston University, Boston, MA;
SPONSOR NAME: Kathryn Fallows
CONTACT (E-MAIL ONLY): kfallows@bu.edu
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