Radio occultation measurement of the electron density near the lunar surface using a subsatellite on the SELENE mission

T. Imamura, A. Nabatov, N. Mochizuki, T. Iwata, H. Hanada, K. Matsumoto, H. Noda, Y. Kono, Q. Liu, Y. Futaana, H. Ando, Z. Yamamoto, Oyama Koichiro, A. Saito

Research output: Contribution to journalArticle

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Abstract

The electron density distribution in the vicinity of the lunar surface was explored with the radio occultation technique using a subsatellite on the SELENE mission. Although the measurements suffer from contamination by the terrestrial ionosphere and interplanetary plasma, an analysis of more than 300 measurements provides adequate statistics and reveals a general trend. The result suggests that a dense ionosphere covering the whole sunlit side, as suggested by the radio occultation measurements on the Soviet Luna 19 and 22 missions, does not exist. However, weak signatures of electron density enhancement with densities on the order of 100 cm-3 are observed below 30 km altitude at solar zenith angles less than 60. The statistically averaged density reaches a peak at around 15 km altitude and decreases gradually at higher altitudes and toward the surface. Although the suggested electron layer is thinner and less extended horizontally than that reported by Luna 19 and 22, the existence of such an ionized layer is still difficult to explain by conventional ionosphere generation mechanisms. An alternative source of electrons may be required.

Original languageEnglish
Article numberA06303
JournalJournal of Geophysical Research: Space Physics
Volume117
Issue number6
DOIs
Publication statusPublished - 2012 Jan 1

Fingerprint

radio occultation
lunar surface
Ionosphere
radio
electron density
ionospheres
Carrier concentration
ionosphere
electrons
electron
Electronic density of states
Electrons
zenith angle
zenith
high altitude
density distribution
contamination
Contamination
coverings
signatures

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Imamura, T. ; Nabatov, A. ; Mochizuki, N. ; Iwata, T. ; Hanada, H. ; Matsumoto, K. ; Noda, H. ; Kono, Y. ; Liu, Q. ; Futaana, Y. ; Ando, H. ; Yamamoto, Z. ; Koichiro, Oyama ; Saito, A. / Radio occultation measurement of the electron density near the lunar surface using a subsatellite on the SELENE mission. In: Journal of Geophysical Research: Space Physics. 2012 ; Vol. 117, No. 6.
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abstract = "The electron density distribution in the vicinity of the lunar surface was explored with the radio occultation technique using a subsatellite on the SELENE mission. Although the measurements suffer from contamination by the terrestrial ionosphere and interplanetary plasma, an analysis of more than 300 measurements provides adequate statistics and reveals a general trend. The result suggests that a dense ionosphere covering the whole sunlit side, as suggested by the radio occultation measurements on the Soviet Luna 19 and 22 missions, does not exist. However, weak signatures of electron density enhancement with densities on the order of 100 cm-3 are observed below 30 km altitude at solar zenith angles less than 60. The statistically averaged density reaches a peak at around 15 km altitude and decreases gradually at higher altitudes and toward the surface. Although the suggested electron layer is thinner and less extended horizontally than that reported by Luna 19 and 22, the existence of such an ionized layer is still difficult to explain by conventional ionosphere generation mechanisms. An alternative source of electrons may be required.",
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Imamura, T, Nabatov, A, Mochizuki, N, Iwata, T, Hanada, H, Matsumoto, K, Noda, H, Kono, Y, Liu, Q, Futaana, Y, Ando, H, Yamamoto, Z, Koichiro, O & Saito, A 2012, 'Radio occultation measurement of the electron density near the lunar surface using a subsatellite on the SELENE mission', Journal of Geophysical Research: Space Physics, vol. 117, no. 6, A06303. https://doi.org/10.1029/2011JA017293

Radio occultation measurement of the electron density near the lunar surface using a subsatellite on the SELENE mission. / Imamura, T.; Nabatov, A.; Mochizuki, N.; Iwata, T.; Hanada, H.; Matsumoto, K.; Noda, H.; Kono, Y.; Liu, Q.; Futaana, Y.; Ando, H.; Yamamoto, Z.; Koichiro, Oyama; Saito, A.

In: Journal of Geophysical Research: Space Physics, Vol. 117, No. 6, A06303, 01.01.2012.

Research output: Contribution to journalArticle

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AU - Hanada, H.

AU - Matsumoto, K.

AU - Noda, H.

AU - Kono, Y.

AU - Liu, Q.

AU - Futaana, Y.

AU - Ando, H.

AU - Yamamoto, Z.

AU - Koichiro, Oyama

AU - Saito, A.

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N2 - The electron density distribution in the vicinity of the lunar surface was explored with the radio occultation technique using a subsatellite on the SELENE mission. Although the measurements suffer from contamination by the terrestrial ionosphere and interplanetary plasma, an analysis of more than 300 measurements provides adequate statistics and reveals a general trend. The result suggests that a dense ionosphere covering the whole sunlit side, as suggested by the radio occultation measurements on the Soviet Luna 19 and 22 missions, does not exist. However, weak signatures of electron density enhancement with densities on the order of 100 cm-3 are observed below 30 km altitude at solar zenith angles less than 60. The statistically averaged density reaches a peak at around 15 km altitude and decreases gradually at higher altitudes and toward the surface. Although the suggested electron layer is thinner and less extended horizontally than that reported by Luna 19 and 22, the existence of such an ionized layer is still difficult to explain by conventional ionosphere generation mechanisms. An alternative source of electrons may be required.

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