Presentation Abstract

Presentation Number 224.09
Presentation Time: Tuesday, May 24, 2011, 8:00 AM - 7:00 PM
Title The Vertical Structure of the Martian Ionosphere
Author Block Zachary Girazian1, P. Withers1, M. Paetzold2, S. Tellmann2
1Boston University, 2University of Cologne, Germany.
Abstract The vertical structure of the Martian ionosphere consists of two main layers. Maximum electron densities are produced in the M2 layer, which occurs at approximately 140 km, and is created by extreme-ultraviolet solar photons. The weaker M1 layer occurs at approximately 120 km and is produced by solar soft X-rays and associated electron impact ionization. Interpreting the vertical shape of the Martian ionosphere is a key tool for understanding ionosphere behavior and the physical processes involved. The vertical structure of the dayside M2 layer usually consists of a shape similar to idealized Chapman layer theory. However, deviations from this theory are expected as a result of the over-simplified assumptions made by idealized Chapman layer theory. We have investigated 485 vertical electron density profiles from the MaRS radio occultation instrument aboard Mars Express from 2002 to 2010. We will report observations of the vertical structure of the ionosphere of Mars that deviate substantially from the predictions of idealized Chapman layer theory. The examples of unusual M2 layer shapes that we will show include a flat-topped layer, a sharply pointed layer, and a wavy layer. These shapes have not been reproduced by current models of the ionosphere of Mars, which implies significant gaps in our present understanding of the ionosphere of Mars.