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Titolo:
Sunspot plumes and flow channels
Autore:
Brynildsen, N; Maltby, P; Fredvik, T; Kjeldseth-Moe, O; Wilhelm, K;
Indirizzi:
Univ Oslo, Inst Theoret Astrophys, Oslo, Norway Univ Oslo Oslo NorwayUniv Oslo, Inst Theoret Astrophys, Oslo, Norway Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany Max Planck Inst Aeron Katlenburg Lindau Germany D-37191 Lindau, Germany
Titolo Testata:
SOLAR PHYSICS
fascicolo: 1, volume: 198, anno: 2001,
pagine: 89 - 131
SICI:
0038-0938(200101)198:1<89:SPAFC>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
CORONAL DIAGNOSTIC SPECTROMETER; SOLAR TRANSITION ZONE; QUIET-SUN; ULTRAVIOLET-SPECTRUM; EUV SPECTROSCOPY; ACTIVE REGIONS; SOHO; SUMER; LINE; TELESCOPE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Brynildsen, N Univ Oslo, Inst Theoret Astrophys, Oslo, Norway Univ Oslo Oslo Norway nst Theoret Astrophys, Oslo, Norway
Citazione:
N. Brynildsen et al., "Sunspot plumes and flow channels", SOLAR PHYS, 198(1), 2001, pp. 89-131

Abstract

It is well known that sunspots are dark. This statement is not correct in the sunspot atmosphere between the chromosphere and the corona, where sunspots often are brighter than their surroundings. The brightest feature in the sunspot transition region is called a sunspot plume. Not all sunspots contain a plume. We find that 20 out of 21 sunspots show a plume when one magnetic polarity dominates the sunspot region out to a distance of 50" from the sunspot. Most sunspots show downflows that exceed 25 km s(-1) in the sunspot plumes at temperatures close to 250 000 K. This downflow is not maintained by inflow from the corona, but by gas at transition region temperatures, streaming in flow channels from locations well outside the sunspot. We suggest that this inflow is a necessary requirement for the sunspot plume to occur and present a working hypothesis for the origin of sunspot plumes. This paper is the first thorough spectral analysis of sunspot plumes. It is based on simultaneous observations of ten or six EUV emission lines in 42 sunspot regions with the Coronal Diagnostic Spectrometer - CDS on the Solar and Heliospheric Observatory - SOHO. The line profiles are studied in detailwith another SOHO instrument, the Solar Ultraviolet Measurements of Emitted Radiation - SUMER.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/08/20 alle ore 22:09:56