First ENA observations at Mars: Subsolar ENA jet

Y. Futaana; S. Barabash; A. Grigoriev; M. Holmström; E. Kallio; P. C. Brandt; H. Gunell; K. Brinkfeldt; R. Lundin; H. Andersson; M. Yamauchi; S. McKenna-Lawler; J. D. Winningham; R. A. Frahm; J. R. Sharber; J. R. Scherrer; A. J. Coates; D. R. Linder; D. O. Kataria; T. Säles; P. Riihelä; W. Schmidt; H. Koskinen; 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. Orsini; R. Cerulli-Irelli; M. Maggi; P. Wurz; P. Bochsler; N. Krupp; J. Woch; M. Fränz; K. Asamura; C. Dierker

doi:10.1016/j.icarus.2005.08.024

First ENA observations at Mars: Subsolar ENA jet

Y. Futaana^*, S. Barabash, A. Grigoriev, M. Holmström, E. Kallio, P. C. Brandt, H. Gunell, K. Brinkfeldt, R. Lundin, H. Andersson, M. Yamauchi, S. McKenna-Lawler, J. D. Winningham, R. A. Frahm, J. R. Sharber, J. R. Scherrer, A. J. Coates, D. R. Linder, D. O. Kataria, T. SälesP. Riihelä, W. Schmidt, H. Koskinen, 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. Orsini, R. Cerulli-Irelli, M. Maggi, P. Wurz, P. Bochsler, N. Krupp, J. Woch, M. Fränz, K. Asamura, C. Dierker

^*Corresponding author for this work

Department of Physics

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Abstract

The Neutral Particle Detector (NPD), an Energetic Neutral Atom (ENA) sensor of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) on board Mars Express, detected intense fluxes of ENAs emitted from the subsolar region of Mars. The typical ENA fluxes are (4-7) × 10⁵ cm^-2 sr^-1 s^-1 in the energy range 0.3-3 keV. These ENAs are likely to be generated in the subsolar region of the martian exosphere. As the satellite moved away from Mars, the ENA flux decreased while the field of view of the NPD pointed toward the subsolar region. These decreases occurred very quickly with a time scale of a few tens of seconds in two thirds of the orbits. Such a behavior can be explained by the spacecraft crossing a spatially constrained ENA jet, i.e., a highly directional ENA emission from a compact region of the subsolar exosphere. This ENA jet is highly possible to be emitted conically from the subsolar region. Such directional ENAs can result from the anisotropic solar wind flow around the subsolar region, but this can not be explained in the frame of MHD models.

Original language	English
Pages (from-to)	413-423
Number of pages	11
Journal	Icarus
Volume	182
Issue number	2
DOIs	https://doi.org/10.1016/j.icarus.2005.08.024
Publication status	Published - Jun 2006

Keywords

atmosphere
Magnetospheres
Mars
Solar wind

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Futaana, Y., Barabash, S., Grigoriev, A., Holmström, M., Kallio, E., Brandt, P. C., Gunell, H., Brinkfeldt, K., Lundin, R., Andersson, H., Yamauchi, M., McKenna-Lawler, S., Winningham, J. D., Frahm, R. A., Sharber, J. R., Scherrer, J. R., Coates, A. J., Linder, D. R., Kataria, D. O., ... Dierker, C. (2006). First ENA observations at Mars: Subsolar ENA jet. Icarus, 182(2), 413-423. https://doi.org/10.1016/j.icarus.2005.08.024

@article{77b9267051fe4105acbe2813e8cb2ab2,

title = "First ENA observations at Mars: Subsolar ENA jet",

abstract = "The Neutral Particle Detector (NPD), an Energetic Neutral Atom (ENA) sensor of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) on board Mars Express, detected intense fluxes of ENAs emitted from the subsolar region of Mars. The typical ENA fluxes are (4-7) × 105 cm-2 sr-1 s-1 in the energy range 0.3-3 keV. These ENAs are likely to be generated in the subsolar region of the martian exosphere. As the satellite moved away from Mars, the ENA flux decreased while the field of view of the NPD pointed toward the subsolar region. These decreases occurred very quickly with a time scale of a few tens of seconds in two thirds of the orbits. Such a behavior can be explained by the spacecraft crossing a spatially constrained ENA jet, i.e., a highly directional ENA emission from a compact region of the subsolar exosphere. This ENA jet is highly possible to be emitted conically from the subsolar region. Such directional ENAs can result from the anisotropic solar wind flow around the subsolar region, but this can not be explained in the frame of MHD models.",

keywords = "atmosphere, Magnetospheres, Mars, Solar wind",

author = "Y. Futaana and S. Barabash and A. Grigoriev and M. Holmstr{\"o}m and E. Kallio and Brandt, {P. C.} and H. Gunell and K. Brinkfeldt and R. Lundin and H. Andersson and M. Yamauchi and S. McKenna-Lawler and Winningham, {J. D.} and Frahm, {R. A.} and Sharber, {J. R.} and Scherrer, {J. R.} and Coates, {A. J.} and Linder, {D. R.} and Kataria, {D. O.} and T. S{\"a}les and P. Riihel{\"a} and W. Schmidt and H. Koskinen and J. Kozyra and J. Luhmann and E. Roelof and D. Williams and S. Livi and Curtis, {C. C.} and Hsieh, {K. C.} and Sandel, {B. R.} and M. Grande and M. Carter and Sauvaud, {J. A.} and A. Fedorov and Thocaven, {J. J.} and S. Orsini and R. Cerulli-Irelli and M. Maggi and P. Wurz and P. Bochsler and N. Krupp and J. Woch and M. Fr{\"a}nz and K. Asamura and C. Dierker",

note = "Funding Information: The ASPERA-3 experiment on the European Space Agency (ESA) Mars Express is a joint effort by 15 laboratories in 10 countries, all supported by their national agencies. We thank all these agencies, as well as the various departments and institutes hosting these efforts. Y. Futaana is supported by Postdoctoral Fellowships for Research Abroad of the Japan Society for the Promotion Science. Copyright: Copyright 2006 Elsevier B.V., All rights reserved.",

year = "2006",

month = jun,

doi = "10.1016/j.icarus.2005.08.024",

language = "English",

volume = "182",

pages = "413--423",

journal = "Icarus",

issn = "0019-1035",

publisher = "Elsevier",

number = "2",

}

Futaana, Y, Barabash, S, Grigoriev, A, Holmström, M, Kallio, E, Brandt, PC, Gunell, H, Brinkfeldt, K, Lundin, R, Andersson, H, Yamauchi, M, McKenna-Lawler, S, Winningham, JD, Frahm, RA, Sharber, JR, Scherrer, JR, Coates, AJ, Linder, DR, Kataria, DO, Säles, T, Riihelä, P, Schmidt, W, Koskinen, H, Kozyra, J, Luhmann, J, Roelof, E, Williams, D, Livi, S, Curtis, CC, Hsieh, KC, Sandel, BR, Grande, M, Carter, M, Sauvaud, JA, Fedorov, A, Thocaven, JJ, Orsini, S, Cerulli-Irelli, R, Maggi, M, Wurz, P, Bochsler, P, Krupp, N, Woch, J, Fränz, M, Asamura, K & Dierker, C 2006, 'First ENA observations at Mars: Subsolar ENA jet', Icarus, vol. 182, no. 2, pp. 413-423. https://doi.org/10.1016/j.icarus.2005.08.024

TY - JOUR

T1 - First ENA observations at Mars

T2 - Subsolar ENA jet

AU - Futaana, Y.

AU - Barabash, S.

AU - Grigoriev, A.

AU - Holmström, M.

AU - Kallio, E.

AU - Brandt, P. C.

AU - Gunell, H.

AU - Brinkfeldt, K.

AU - Lundin, R.

AU - Andersson, H.

AU - Yamauchi, M.

AU - McKenna-Lawler, S.

AU - Winningham, J. D.

AU - Frahm, R. A.

AU - Sharber, J. R.

AU - Scherrer, J. R.

AU - Coates, A. J.

AU - Linder, D. R.

AU - Kataria, D. O.

AU - Säles, T.

AU - Riihelä, P.

AU - Schmidt, W.

AU - Koskinen, H.

AU - Kozyra, J.

AU - Luhmann, J.

AU - Roelof, E.

AU - Williams, D.

AU - Livi, S.

AU - Curtis, C. C.

AU - Hsieh, K. C.

AU - Sandel, B. R.

AU - Grande, M.

AU - Carter, M.

AU - Sauvaud, J. A.

AU - Fedorov, A.

AU - Thocaven, J. J.

AU - Orsini, S.

AU - Cerulli-Irelli, R.

AU - Maggi, M.

AU - Wurz, P.

AU - Bochsler, P.

AU - Krupp, N.

AU - Woch, J.

AU - Fränz, M.

AU - Asamura, K.

AU - Dierker, C.

N1 - Funding Information: The ASPERA-3 experiment on the European Space Agency (ESA) Mars Express is a joint effort by 15 laboratories in 10 countries, all supported by their national agencies. We thank all these agencies, as well as the various departments and institutes hosting these efforts. Y. Futaana is supported by Postdoctoral Fellowships for Research Abroad of the Japan Society for the Promotion Science. Copyright: Copyright 2006 Elsevier B.V., All rights reserved.

PY - 2006/6

Y1 - 2006/6

N2 - The Neutral Particle Detector (NPD), an Energetic Neutral Atom (ENA) sensor of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) on board Mars Express, detected intense fluxes of ENAs emitted from the subsolar region of Mars. The typical ENA fluxes are (4-7) × 105 cm-2 sr-1 s-1 in the energy range 0.3-3 keV. These ENAs are likely to be generated in the subsolar region of the martian exosphere. As the satellite moved away from Mars, the ENA flux decreased while the field of view of the NPD pointed toward the subsolar region. These decreases occurred very quickly with a time scale of a few tens of seconds in two thirds of the orbits. Such a behavior can be explained by the spacecraft crossing a spatially constrained ENA jet, i.e., a highly directional ENA emission from a compact region of the subsolar exosphere. This ENA jet is highly possible to be emitted conically from the subsolar region. Such directional ENAs can result from the anisotropic solar wind flow around the subsolar region, but this can not be explained in the frame of MHD models.

AB - The Neutral Particle Detector (NPD), an Energetic Neutral Atom (ENA) sensor of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) on board Mars Express, detected intense fluxes of ENAs emitted from the subsolar region of Mars. The typical ENA fluxes are (4-7) × 105 cm-2 sr-1 s-1 in the energy range 0.3-3 keV. These ENAs are likely to be generated in the subsolar region of the martian exosphere. As the satellite moved away from Mars, the ENA flux decreased while the field of view of the NPD pointed toward the subsolar region. These decreases occurred very quickly with a time scale of a few tens of seconds in two thirds of the orbits. Such a behavior can be explained by the spacecraft crossing a spatially constrained ENA jet, i.e., a highly directional ENA emission from a compact region of the subsolar exosphere. This ENA jet is highly possible to be emitted conically from the subsolar region. Such directional ENAs can result from the anisotropic solar wind flow around the subsolar region, but this can not be explained in the frame of MHD models.

KW - atmosphere

KW - Magnetospheres

KW - Mars

KW - Solar wind

UR - http://www.scopus.com/inward/record.url?scp=33747347324&partnerID=8YFLogxK

U2 - 10.1016/j.icarus.2005.08.024

DO - 10.1016/j.icarus.2005.08.024

M3 - Article

AN - SCOPUS:33747347324

SN - 0019-1035

VL - 182

SP - 413

EP - 423

JO - Icarus

JF - Icarus

IS - 2

ER -

First ENA observations at Mars: Subsolar ENA jet

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