New suprathermal proton population around the Moon: Observation by SARA on Chandrayaan-1

Dhanya, M. B.; Bhardwaj, Anil; Futaana, Yoshifumi; Barabash, Stas; Wieser, Martin; Holmström, Mats; Wurz, Peter (2017). New suprathermal proton population around the Moon: Observation by SARA on Chandrayaan-1. Geophysical Research Letters, 44(10), pp. 4540-4548. American Geophysical Union 10.1002/2017GL072605

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We report a new population of suprathermal H⁺(~1.5–3 times the solar wind energy) around the Moon observed by Solar Wind Monitor (SWIM)/Sub-keV Atom Reflecting Analyzer (SARA) on Chandrayaan-1. These ions have large initial velocity (>100 km s⁻¹ ) and are observed on the dayside, near the terminator, and in the near-wake region (100–200 k m above the surface), when the Moon is located outside Earth’s bow shock. Backtracing suggests that the source is located >500 km above the dayside lunar surface. Possible sources considered for these ions are ionization of backscattered lunar energetic neutral hydrogen atoms, ionization of lunar exospheric hydrogen, inner source pickup ions, interstellar pickup ions, ionization of neutral solar wind, and solar wind H⁺ reflected from Earth’s bow shock. The comparison of the observed flux (density) with that expected from these sources and the velocity distribution suggests that an additional source is required to explain the population.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute

UniBE Contributor:

Wurz, Peter

Subjects:

500 Science > 530 Physics

ISSN:

0094-8276

Publisher:

American Geophysical Union

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

29 Sep 2017 10:56

Last Modified:

01 Dec 2017 02:33

Publisher DOI:

10.1002/2017GL072605

BORIS DOI:

10.7892/boris.105592

URI:

https://boris.unibe.ch/id/eprint/105592

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