Radar Soundings of the Ionosphere of Mars
D. A. Gurnett,1*
D. L. Kirchner,1
R. L. Huff,1
D. D. Morgan,1
A. M. Persoon,1
T. F. Averkamp,1
F. Duru,1
E. Nielsen,2
A. Safaeinili,3
J. J. Plaut,3
G. Picardi4
We report the first radar soundings of the ionosphere of Mars with the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument on board the orbiting Mars Express spacecraft. Several types of ionospheric echoes are observed, ranging from vertical echoes caused by specular reflection from the horizontally stratified ionosphere to a wide variety of oblique and diffuse echoes. The oblique echoes are believed to arise mainly from ionospheric structures associated with the complex crustal magnetic fields of Mars. Echoes at the electron plasma frequency and the cyclotron period also provide measurements of the local electron density and magnetic field strength.
1 Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA.
2 Max Planck Institute for Solar System Research, 37191 Katlenburg-Lindau, Germany.
3 Jet Propulsion Laboratory, Pasadena, CA 91109, USA.
4 Infocom Department, "La Sapienza" University of Rome, 00184 Rome, Italy.
* To whom correspondence should be addressed. E-mail: donald-gurnett{at}uiowa.edu
