Energetic particle composition measurements from Phobos 2

Results of the LET experiment

R. G. Marsden, K. P. Wenzel, V. V. Afonin, K. Gringauz, M. Witte, A. K. Richter, G. Erdős, A. J. Somogyi, A. Varga, L. Varhalmi

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The Low Energy Telescope (LET) experiment carried on board the Phobos spacecraft measured the flux, spectra and elemental composition of nuclei from hydrogen up to iron, in the energy range ∼ 1-75 MeV nucleon-1. Isotope separation for helium was also achieved. We present the results of a study of solar energetic particle (SEP) composition using LET data acquired during the period July 1988 to March 1989. The set of particle events selected for study comprises six large solar flare events, two 3He-rich events and two energetic storm particle increases associated with interplanetary shocks. Three of the six large flare events occurred during a period of unusually high solar activity in March 1989. In two of these events, large Fe/O ratios were measured (0.44 ± 0.05 and 0.95 ± 0.24). The Fe/O ratios determined for the complete set of large flare events show an inverse correlation with the spectral index of oxygen, suggesting that the acceleration mechanism that produces events showing enhanced heavy-ion abundances is different from that responsible for lower Fe/O ratios. Our results in the case of the 3He-rich events are in agreement with earlier work, showing an enrichment in heavy ions relative to the average SEP composition. The abundances measured for the shock-associated increases are consistent with the acceleration of the ambient population of solar flare particles.

Original languageEnglish
Pages (from-to)57-66
Number of pages10
JournalPlanetary and Space Science
Volume39
Issue number1-2
DOIs
Publication statusPublished - 1991

Fingerprint

Phobos
energetic particles
energetics
telescopes
energy
experiment
solar flares
ion
flares
Phobos spacecraft
heavy ions
solar activity
helium
interplanetary shock waves
isotope separation
spacecraft
particle
hydrogen
isotope
iron

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Marsden, R. G., Wenzel, K. P., Afonin, V. V., Gringauz, K., Witte, M., Richter, A. K., ... Varhalmi, L. (1991). Energetic particle composition measurements from Phobos 2: Results of the LET experiment. Planetary and Space Science, 39(1-2), 57-66. https://doi.org/10.1016/0032-0633(91)90126-U

Energetic particle composition measurements from Phobos 2 : Results of the LET experiment. / Marsden, R. G.; Wenzel, K. P.; Afonin, V. V.; Gringauz, K.; Witte, M.; Richter, A. K.; Erdős, G.; Somogyi, A. J.; Varga, A.; Varhalmi, L.

In: Planetary and Space Science, Vol. 39, No. 1-2, 1991, p. 57-66.

Research output: Contribution to journalArticle

Marsden, RG, Wenzel, KP, Afonin, VV, Gringauz, K, Witte, M, Richter, AK, Erdős, G, Somogyi, AJ, Varga, A & Varhalmi, L 1991, 'Energetic particle composition measurements from Phobos 2: Results of the LET experiment', Planetary and Space Science, vol. 39, no. 1-2, pp. 57-66. https://doi.org/10.1016/0032-0633(91)90126-U
Marsden, R. G. ; Wenzel, K. P. ; Afonin, V. V. ; Gringauz, K. ; Witte, M. ; Richter, A. K. ; Erdős, G. ; Somogyi, A. J. ; Varga, A. ; Varhalmi, L. / Energetic particle composition measurements from Phobos 2 : Results of the LET experiment. In: Planetary and Space Science. 1991 ; Vol. 39, No. 1-2. pp. 57-66.
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