Study of the Ionospheres of Mars and earth under magnetic and dust storm conditions

Abstract

The objective of this proposal is to analyze Mars Global Surveyor (MGS) and Mars Express (MEX) data in the ionosphere of Mars and compare them with the earth's ionosphere. The modeling of these data will be carried out using a model including continuity, momentum and energy balance equation for electrons and ions. The heating/cooling, energy absorption/emission processes and chemistry of various ions are proposed to be solved in this model calculation. The long term and short -term variability in the ionosphere will also be studied to understand the solar and dust influence on climate/weather of Mars and earth. The calculated results will be compared with the observations.The proposed research will follow the topics as given below:(1) The ionosphere of Mars has been explored during the encounters of Mariner 6, 7 and 9, Mars 2, 3, 4, 6 and 7, Viking 1 and 2 and recently by Mars Global Surveyor (MGS) and Mars Express (MEX). The daytime ionosphere models, which consider ionization by solar radiation, explain electron density measurements obtained from these satellites. The night side ionospheric models considering the precipitation of solar wind electrons agree with the Viking radio observations. In spite of the relatively large number of measurements and models the effect of magnetic and dust storms are not understood in the ionosphere of Mars. The magnetic storms occur on earth as a result of an unusually intense interaction between solar wind and magnetosphere. Mars has no significant magnetic field. The solar wind interacts directly with the ionosphere of Mars. MGS and MEX have observed direction of interplanetary magnetic field in the Martian ionosphere. The study of magnetic storms and their influences on the Martian ionosphere would be a great achievement. We have a fairly good base of understanding of physical and chemical processes of these events in the earth's ionosphere. It is an appropriate time to analyze the available data of Mars and compare them with the earth's ionosphere to see whether the processes operating in earth's atmosphere hold good or they need scaling up or scaling down or search for new processes to explain the observed sudden commencement/change in the ionosphere of Mars. Radio occultation experiment onboard MGS and MEX have observed the electron density profiles at different latitudes, longitudes and seasons. More extensive observations are in progress from this experiment onboard MEX. These data are publicly available from planetary data centre. We shall use these data in the proposed study.(2) MGS and Mars Odyssey have observed two major dust storms in MY25 and MY28 respectively. (MY stands for Mars Year; MY1 starts on April 11, 1955) During the most intense period of the storm the dust optical depths are found to increase by a factor of 20 from its normal condition. In the second phase we will study the characteristics of Martian ionosphere in presence and absence of dust storms at different latitude, longitude and seasons. The model results will be compared with the existing data of earth's ionosphere obtained from ground based experiments and other satellites. (AU)