Space Science Reviews

, Volume 126, Issue 1, pp 333–354

Auroral Plasma Acceleration Above Martian Magnetic Anomalies

  • R. Lundin
  • D. Winningham
  • S. Barabash
  • R. Frahm
  • D. Brain
  • H. Nilsson
  • M. Holmström
  • M. Yamauchi
  • J. R. Sharber
  • J.-A. Sauvaud
  • A. Fedorov
  • K. Asamura
  • H. Hayakawa
  • A. J. Coates
  • Y. Soobiah
  • C. Curtis
  • K. C. Hsieh
  • M. Grande
  • H. Koskinen
  • E. Kallio
  • J. Kozyra
  • J. Woch
  • M. Fraenz
  • J. Luhmann
  • S. Mckenna-Lawler
  • S. Orsini
  • P. Brandt
  • P. Wurz
Article

DOI: 10.1007/s11214-006-9086-x

Cite this article as:
Lundin, R., Winningham, D., Barabash, S. et al. Space Sci Rev (2006) 126: 333. doi:10.1007/s11214-006-9086-x

Abstract

Aurora is caused by the precipitation of energetic particles into a planetary atmosphere, the light intensity being roughly proportional to the precipitating particle energy flux. From auroral research in the terrestrial magnetosphere it is known that bright auroral displays, discrete aurora, result from an enhanced energy deposition caused by downward accelerated electrons. The process is commonly referred to as the auroral acceleration process. Discrete aurora is the visual manifestation of the structuring inherent in a highly magnetized plasma. A strong magnetic field limits the transverse (to the magnetic field) mobility of charged particles, effectively guiding the particle energy flux along magnetic field lines.

The typical, slanted arc structure of the Earth’s discrete aurora not only visualizes the inclination of the Earth’s magnetic field, but also illustrates the confinement of the auroral acceleration process. The terrestrial magnetic field guides and confines the acceleration processes such that the preferred acceleration of particles is frequently along the magnetic field lines. Field-aligned plasma acceleration is therefore also the signature of strongly magnetized plasma.

This paper discusses plasma acceleration characteristics in the night-side cavity of Mars. The acceleration is typical for strongly magnetized plasmas – field-aligned acceleration of ions and electrons. The observations map to regions at Mars of what appears to be sufficient magnetization to support magnetic field-aligned plasma acceleration – the localized crustal magnetizations at Mars (Acuña et al., 1999). Our findings are based on data from the ASPERA-3 experiment on ESA’s Mars Express, covering 57 orbits traversing the night-side/eclipse of Mars. There are indeed strong similarities between Mars and the Earth regarding the accelerated electron and ion distributions. Specifically acceleration above Mars near local midnight and acceleration above discrete aurora at the Earth – characterized by nearly monoenergetic downgoing electrons in conjunction with nearly monoenergetic upgoing ions. We describe a number of characteristic features in the accelerated plasma: The “inverted V” energy-time distribution, beam vs temperature distribution, altitude distribution, local time distribution and connection with magnetic anomalies. We also compute the electron energy flux and find that the energy flux is sufficient to cause weak to medium strong (up to several tens of kR 557.7 nm emissions) aurora at Mars.

Monoenergetic counterstreaming accelerated ions and electrons is the signature of field-aligned electric currents and electric field acceleration. The topic is reasonably well understood in terrestrial magnetospheric physics, although some controversy still remains on details and the cause-effect relationships. We present a potential cause-effect relationship leading to auroral plasma acceleration in the nightside cavity of Mars – the downward acceleration of electrons supposedly manifesting itself as discrete aurora above Mars.

Keywords

auroraplasma accelerationMars magnetic anomalies

Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  • R. Lundin
    • 1
  • D. Winningham
    • 2
  • S. Barabash
    • 1
  • R. Frahm
    • 2
  • D. Brain
    • 11
  • H. Nilsson
    • 1
  • M. Holmström
    • 1
  • M. Yamauchi
    • 1
  • J. R. Sharber
    • 2
  • J.-A. Sauvaud
    • 3
  • A. Fedorov
    • 3
  • K. Asamura
    • 4
  • H. Hayakawa
    • 4
  • A. J. Coates
    • 5
  • Y. Soobiah
    • 5
  • C. Curtis
    • 6
  • K. C. Hsieh
    • 6
  • M. Grande
    • 7
  • H. Koskinen
    • 8
  • E. Kallio
    • 8
  • J. Kozyra
    • 9
  • J. Woch
    • 10
  • M. Fraenz
    • 10
  • J. Luhmann
    • 11
  • S. Mckenna-Lawler
    • 12
  • S. Orsini
    • 13
  • P. Brandt
    • 14
  • P. Wurz
    • 15
  1. 1.Swedish Institute of Space PhysicsKirunaSweden
  2. 2.Southwest Research InstituteSan AntonioUSA
  3. 3.Centre d’Etude Spatiale des RayonnementsToulouseFrance
  4. 4.Institute of Space and Astronautical ScienceSagamicharaJapan
  5. 5.Mullard Space Science LaboratoryUniversity College LondonSurreyUK
  6. 6.University of ArizonaTucsonUSA
  7. 7.Rutherford Appleton LaboratoryOxfordshireUK
  8. 8.Finnish Meteorological InstituteHelsinkiFinland
  9. 9.Space Physics Research Lab.University of MichiganAnn ArborUSA
  10. 10.Max-Planck-Institut für SonnensystemforschungKatlenburg-LindauGermany
  11. 11.Space Science Lab.University of California in BerkeleyBerkeleyUSA
  12. 12.Space Technology Ltd.National University of IrelandMaynoothIreland
  13. 13.Instituto di Fisica dello Spazio InterplanetariRomeItaly
  14. 14.Applied Physics LaboratoryJohns Hopkins UniversityLaurelUSA
  15. 15.University of Bern, Physikalisches InstitutBernSwitzerland