First ENA observations at Mars: Solar-wind ENAs on the nightside

K. Brinkfeldt*, H. Gunell, P. C. Brandt, S. Barabash, R. A. Frahm, J. D. Winningham, E. Kallio, M. Holmström, Y. Futaana, A. Ekenbäck, R. Lundin, H. Andersson, M. Yamauchi, A. Grigoriev, J. R. Sharber, J. R. Scherrer, A. J. Coates, D. R. Linder, D. O. Kataria, H. KoskinenT. Säles, P. Riihelä, W. Schmidt, J. Kozyra, J. Luhmann, E. Roelof, D. Williams, S. Livi, C. C. Curtis, K. C. Hsieh, B. R. Sandel, M. Grande, M. Carter, J. A. Sauvaud, A. Fedorov, J. J. Thocaven, S. McKenna-Lawler, S. Orsini, R. Cerulli-Irelli, M. Maggi, P. Wurz, P. Bochsler, N. Krupp, J. Woch, M. Fränz, K. Asamura, C. Dierker

*Awdur cyfatebol y gwaith hwn

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

26 Dyfyniadau (Scopus)

Crynodeb

We present measurements with an Energetic Neutral Atom (ENA) imager on board Mars Express when the spacecraft moves into Mars eclipse. Solar wind ions charge exchange with the extended Mars exosphere to produce ENAs that can spread into the eclipse of Mars due to the ions' thermal spread. Our measurements show a lingering signal from the Sun direction for several minutes as the spacecraft moves into the eclipse. However, our ENA imager is also sensitive to UV photons and we compare the measurements to ENA simulations and a simplified model of UV scattering in the exosphere. Simulations and further comparisons with an electron spectrometer sensitive to photoelectrons generated when UV photons interact with the spacecraft suggest that what we are seeing in Mars' eclipse are ENAs from upstream of the bow shock produced in charge exchange with solar wind ions with a non-zero temperature. The measurements are a precursor to a new technique called ENA sounding to measure solar wind and planetary exosphere properties in the future.

Iaith wreiddiolSaesneg
Tudalennau (o-i)439-447
Nifer y tudalennau9
CyfnodolynIcarus
Cyfrol182
Rhif cyhoeddi2
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - Meh 2006

Ôl bys

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