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M. Mendillo, S. Smith, C. Martinis, J. Wilson, L. Moore (Boston University), D. Hinson (Stanford University)
The day-to-day variability of a planet's ionosphere arises from a complex mixture of photo-chemistry, neutral-ion coupling, and electro-dynamics. Until recently, the study of ionospheric perturbations has been possible only on Earth where decades of daily observations have been made. The radio science experiment onboard Mars Global Surveyor (MGS)has yielded the first set of electron density profiles capable of supporting studies of day-to-day variability of an ionosphere on another planets. At altitudes of the peak electron density on Mars, photo-chemical equilibrium is the dominant process and thus the observed variability should be consistent with an E-region-like terrestrial ionosphere. We have examined comparable conditions of solar zenith angle on Earth at ionosonde stations on the same days as MGS observations were made on Mars. We find comparable variabiity patterns, and interpret the results using a simple photo-chemical simulation model.