Cislunar plasma exploration with the SELENE radio science system

Oyama, K.‐I.; Nabatov, A. S.; Savich, N. A.; Imamura, Takeshi; Yamamoto, Z.; Noguchi, K.

doi:10.1016/s0273-1177(02)00488-x

Cited by 6 publications

(4 citation statements)

References 4 publications

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“…The radio occultation experiment on SELENE (SELenological and ENgineering Explorer) or Kaguya mission of Japan provides opportunities to understand the lunar electromagnetic environment from a systematic study of the electron density distribution near the lunar surface [ Oyama et al , 2002; Nabatov et al , 2003; Imamura et al , 2008, 2010]. The observations were conducted in two different modes: one is a conventional method using a single spacecraft, and the other is a newly developed dual‐spacecraft method.…”

Section: Introductionmentioning

confidence: 99%

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

Imamura

Nabatov²,

Mochizuki

et al. 2012

J. Geophys. Res.

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[1] 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 À3 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.Citation: Imamura, T., et al. (2012), Radio occultation measurement of the electron density near the lunar surface using a subsatellite on the SELENE mission,

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Section: Introductionmentioning

confidence: 99%

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

Imamura

Nabatov²,

Mochizuki

et al. 2012

J. Geophys. Res.

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“…The frequency of the transmitted wave will change with the oscillator temperature by ∼300 Hz K −1 in the S-band (∼2.2 GHz for Vstar and Rstar) and by ∼1000 Hz K −1 in the X-band (∼8.4 GHz for Vstar). Although the onboard oscillator is not very stable, taking a linear combination of the phases in the two coherent bands enables us to distinguish the plasma contributions from the fluctuation in the oscillator output frequency (Oyama et al , 2002. The two coherent bands are S-and X-bands or two S-bands as described in the next section.…”

Section: Spacecraft and Recording Systemmentioning

confidence: 99%

“…The radio occultation experiment, which is also termed Radio Science (RS), in the SELENE (SELenological and Engineering Explorer) or Kaguya mission of Japan provides opportunities to systematically study this ionized layer to examine its existence and to understand the generation mechanism if it exists (Oyama et al 2002;Nabatov et al 2003). The present paper focuses on the technical aspects of this experiment rather than scientific results.…”

Section: Introductionmentioning

confidence: 99%

Studying the Lunar Ionosphere with SELENE Radio Science Experiment

et al. 2010

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Radio occultation observations of the electron density near the lunar surface were conducted during the SELENE (Kaguya) mission using the Vstar and Rstar sub-satellites. Previous radio occultation measurements conducted in the Soviet lunar missions have indicated the existence of an ionosphere with peak densities of several hundreds of electrons per cubic centimeters above the dayside lunar surface. These densities are difficult to explain theoretically when the removal of plasma by the solar wind is considered, and thus the generation mechanism of the lunar ionosphere is a major issue, with even the validity of previous observations still under debate. The most serious error source in the measurement T. Imamura ( ) · T. Iwata · Z.-i. Yamamoto · N. Mochizuki

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“…The radio science (RS) experiments in the SELENE (SELenological and Engineering Explorer) mission will provide opportunities to systematically study this ionized layer to examine its existence and to understand the generation mechanism (Oyama et al, 2002;Nabatov et al, 2003). The following sections describe the method of observation.…”

Section: Introductionmentioning

confidence: 99%

The possibility of studying the lunar ionosphere with the SELENE radio science experiment

et al. 2008

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The electron density profiles above the lunar surface will be observed by the radio occultation technique during the SELENE mission using the Vstar sub-satellite. Previous radio occultation observations have indicated the existence of an ionosphere with densities of up to 1000 cm −3 above the dayside lunar surface. The measured densities are difficult to explain theoretically when the removal of plasma by the solar wind is considered, and thus the generation mechanism of the lunar ionosphere is a major issue, with even the validity of previous observations still under debate. The SELENE radio science experiment will establish the morphology of the lunar ionosphere and will reveal its relationship with various physical conditions to provide possible clues to the mechanism.

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Cislunar plasma exploration with the SELENE radio science system

Cited by 6 publications

References 4 publications

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

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

Studying the Lunar Ionosphere with SELENE Radio Science Experiment

The possibility of studying the lunar ionosphere with the SELENE radio science experiment

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