Document Type

Article

Publication Date

7-9-1993

Abstract

The nightside ionosphere of Mars could be produced by electron precipitation or by plasma transport from the dayside, by analogy to the Venus, but few measurements are available. We report here model calculations of upper limits to the nightside ion densities on Mars that would be produced by both mechanisms. For the auroral model, we have adopted the downward traveling portions of the electron spectra measured by the HARP instrument on the Soviet Phobos spacecraft in the Martian plasma sheet and in the magnetotail lobes. For the plasma transport case, we have imposed on a model of the nightside thermosphere, downward fluxes of O+, C+, N+, NO+ and O+2 that are near the maximum upward fluxes that can be sustained by the dayside ionosphere. The computed electron density peaks are in the range (1.3–1.9) × 104 cm−3 at altitudes of 159 to 179 km. The major ion for all the models is O+2, but significant differences in the composition of the minor ions are found for the ionospheres produced by auroral precipitation and by plasma transport. The calculations reported here provide a guide to the data that should be acquired during a future aeronomy mission to Mars, in order to determine the sources of the nightside ionosphere.

Comments

Copyright © 1993 by the American Geophysical Union.

The following article appeared in Geophysical Research Letters 20(13), and may be found at http://onlinelibrary.wiley.com/doi/10.1029/93GL01349/full

Permission to Deposit an Article in an Institutional Repository:

Adopted by Council 13 December 2009.

AGU allows authors to deposit their journal articles if the version is the final published citable version of record, the AGU copyright statement is clearly visible on the posting, and the posting is made 6 months after official publication by the AGU.

DOI

10.1029/93GL01349

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