Universität zu Köln

Imamura, Takeshi, Tokumaru, Munetoshi, Isobe, Hiroaki, Shiota, Daikou ORCID: 0000-0002-9032-8792, Ando, Hiroki, Miyamoto, Mayu, Toda, Tomoaki, Haeusler, Bernd, Paetzold, Martin, Nabatov, Alexander, Asai, Ayumi, Yaji, Kentaro, Yamada, Manabu and Nakamura, Masato (2014). OUTFLOW STRUCTURE OF THE QUIET SUN CORONA PROBED BY SPACECRAFT RADIO SCINTILLATIONS IN STRONG SCATTERING. Astrophys. J., 788 (2). BRISTOL: IOP PUBLISHING LTD. ISSN 1538-4357

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Abstract

Radio scintillation observations have been unable to probe flow speeds in the low corona where the scattering of radio waves is exceedingly strong. Here we estimate outflow speeds continuously from the vicinity of the Sun to the outer corona (heliocentric distances of 1.5-20.5 solar radii) by applying the strong scattering theory to radio scintillations for the first time, using the Akatsuki spacecraft as the radio source. Small, nonzero outflow speeds were observed over a wide latitudinal range in the quiet-Sun low corona, suggesting that the supply of plasma from closed loops to the solar wind occurs over an extended area. The existence of power-law density fluctuations down to the scale of 100 m was suggested, which is indicative of well-developed turbulence which can play a key role in heating the corona. At higher altitudes, a rapid acceleration typical of radial open fields is observed, and the temperatures derived from the speed profile show a distinct maximum in the outer corona. This study opened up a possibility of observing detailed flow structures near the Sun from a vast amount of existing interplanetary scintillation data.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Imamura, Takeshi UNSPECIFIED UNSPECIFIED UNSPECIFIED Tokumaru, Munetoshi UNSPECIFIED UNSPECIFIED UNSPECIFIED Isobe, Hiroaki UNSPECIFIED UNSPECIFIED UNSPECIFIED Shiota, Daikou UNSPECIFIED orcid.org/0000-0002-9032-8792 UNSPECIFIED Ando, Hiroki UNSPECIFIED UNSPECIFIED UNSPECIFIED Miyamoto, Mayu UNSPECIFIED UNSPECIFIED UNSPECIFIED Toda, Tomoaki UNSPECIFIED UNSPECIFIED UNSPECIFIED Haeusler, Bernd UNSPECIFIED UNSPECIFIED UNSPECIFIED Paetzold, Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Nabatov, Alexander UNSPECIFIED UNSPECIFIED UNSPECIFIED Asai, Ayumi UNSPECIFIED UNSPECIFIED UNSPECIFIED Yaji, Kentaro UNSPECIFIED UNSPECIFIED UNSPECIFIED Yamada, Manabu UNSPECIFIED UNSPECIFIED UNSPECIFIED Nakamura, Masato UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-435671
DOI:	10.1088/0004-637X/788/2/117
Journal or Publication Title:	Astrophys. J.
Volume:	788
Number:	2
Date:	2014
Publisher:	IOP PUBLISHING LTD
Place of Publication:	BRISTOL
ISSN:	1538-4357
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SOLAR-WIND ACCELERATION; INTERPLANETARY SCINTILLATION; DENSITY-FLUCTUATIONS; NOZOMI SPACECRAFT; FARADAY-ROTATION; ALFVEN WAVES; SOUNDING EXPERIMENTS; MAGNETIC-FIELDS; POWER SPECTRUM; VENUS ORBITER Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/43567