Mass composition of the escaping plasma at Mars
2006 (English)In: Icarus (New York, N.Y. 1962), ISSN 0019-1035, E-ISSN 1090-2643, Vol. 182, no 2, 320-328 p.Article in journal (Refereed) Published
Data from the Ion Mass Analyzer (IMA) sensor of the ASPERA-3 instrument suite on Mars Express have been analyzed to determine the mass composition of the escaping ion species at Mars. We have examined 77 different ion-beam events and we present the results in terms of flux ratios between the following ion species: CO2+/O+ and O-2(+)/O+. The following ratios averaged over all events and energies were identified: CO2+/O+ = 0.2 and O-2(+)/O+ = 0.9. The values measured are significantly higher, by a factor of 10 for O-2(+)/O+, than a contemporary modeled ratio for the maximum fluxes which the martian ionosphere can supply. The most abundant ion species was found to be O+, followed by O-2(+) and CO2+. We estimate the loss of CO2+ to be 4.0 x 10(24) s(-1) (0.29 kg s(-1)) by using the previous measurements of Phobos-2 in our calculations. The dependence of the ion ratios in relation to their energy ranges we studied, 0.3-3.0 keV, indicated that no clear correlation was found.
Place, publisher, year, edition, pages
2006. Vol. 182, no 2, 320-328 p.
Research subject Fysik
IdentifiersURN: urn:nbn:se:ltu:diva-12585DOI: 10.1016/j.icarus.2005.09.020Local ID: bc01bae0-9c23-11db-8975-000ea68e967bOAI: oai:DiVA.org:ltu-12585DiVA: diva2:985536
Validerad; 2006; Bibliografisk uppgift: Se artikeln för de andra 46 medförfattarna.; 20070104 (pafi)2016-09-292016-09-29Bibliographically approved