|
|||||
|
|
First ENA observations at Mars: ENA emissions from the martian upper atmosphere |
|
| Authors: | Y Futaana S Barabash M Holmström E Kallio H Gunell R Lundin M Yamauchi JD Winningham JR Sharber AJ Coates DO Kataria P Riihelä H Koskinen J Luhmann D Williams CC Curtis BR Sandel M Carter A Fedorov S Orsini M Maggi P Bochsler N Krupp M Fränz C Dierker |
| Institution: | a Swedish Institute of Space Physics, Box 812, SE-981 28 Kiruna, Sweden b NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA c Finnish Meteorological Institute, Box 503, FIN-00101 Helsinki, Finland d Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723-6099, USA e Space Technology Ireland, National University of Ireland, Maynooth, Co. Kildare, Ireland f Southwest Research Institute, San Antonio, TX 7228-0510, USA g Mullard Space Science Laboratory, University College London, Surrey RH5 6NT, UK h University of Helsinki, Department of Physical Sciences, P.O. Box 64, 00014 Helsinki, Finland i Space Physics Research Laboratory, University of Michigan, Ann Arbor, MI 48109-2143, USA j Space Science Laboratory, University of California in Berkeley, Berkeley, CA 94720-7450, USA k University of Arizona, Tucson, AZ 85721, USA l Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK m Centre d'Etude Spatiale des Rayonnements, BP-4346, F-31028 Toulouse, France n Istituto di Fisica dello Spazio Interplanetari, I-00133 Rome, Italy o Physikalisches Institut, University of Bern, CH-3012 Bern, Switzerland p Max-Planck-Institut für Aeronomie, D-37191 Katlenburg-Lindau, Germany q Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Japan r Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig, Germany |
| Abstract: | The neutral particle detector (NPD) on board Mars Express has observed energetic neutral atoms (ENAs) from a broad region on the dayside of the martian upper atmosphere. We show one such example for which the observation was conducted at an altitude of 570 km, just above the induced magnetosphere boundary (IMB). The time of flight spectra of these ENAs show that they had energies of 0.2-2 keV/amu, with an average energy of ∼1.1 keV/amu. Both the spatial distribution and the energy of these ENAs are consistent with the backscattered ENAs, produced by an ENA albedo process. This is the first observation of backscattered ENAs from the martian upper atmosphere. The origin of these ENAs is considered to be the solar wind ENAs that are scattered back by collision processes in the martian upper atmosphere. The particle flux and energy flux of the backscattered ENAs are  and  , respectively. |
| Keywords: | Mars atmosphere Solar wind Atmospheres dynamics Atmospheres structure Ionospheres |
| 本文献已被 ScienceDirect 等数据库收录！ | |