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Titolo:
TIME EVOLUTION OF A MINIFLARE AS SEEN IN H-ALPHA, UV LINES, AND X-RAYS
Autore:
FONTENLA J; SCHMIEDER B; SIMNETT GM; TANDBERGHANSSEN E;
Indirizzi:
UNIV ALABAMA HUNTSVILLE AL 35899 OBSERV PARIS,DASOP,SECT MEUDON F-9215 MEUDON FRANCE UNIV BIRMINGHAM,DEPT PHYS & SPACE RES BIRMINGHAM B15 2TT W MIDLANDS ENGLAND NASA,GEORGE C MARSHALL SPACE FLIGHT CTR HUNTSVILLE AL 35812
Titolo Testata:
The Astrophysical journal
fascicolo: 2, volume: 424, anno: 1994,
parte:, 1
pagine: 1022 -
SICI:
0004-637X(1994)424:2<1022:TEOAMA>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
SOLAR TRANSITION REGION; ENERGY-BALANCE; FLARING LOOPS; GRADUAL PHASE; MODELS; FLARES; SPECTROMETER; EVAPORATION; DIFFUSION; DYNAMICS;
Keywords:
SUN, CHROMOSPHERE; SUN, FLARES; SUN, UV RADIATION; SUN, X-RAYS, GAMMA-RAYS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
26
Recensione:
Indirizzi per estratti:
Citazione:
J. Fontenla et al., "TIME EVOLUTION OF A MINIFLARE AS SEEN IN H-ALPHA, UV LINES, AND X-RAYS", The Astrophysical journal, 424(2), 1994, pp. 1022

Abstract

A miniflare that occurred in active region Hale 16896 on 1980 June 15was observed in Halpha, UV lines, and soft X-rays. These data allow us to analyze the flare emission and derive the energetics and dynamicsof the chromospheric plasma involved. Our results indicate that the energy released by the miniflare was about 10(28) ergs, about four orders of magnitude smaller than that of a large flare. However, hard X-rays (5.5-8.0 keV) were observed which indicated a plasma with temperature as high as 27 x 10(6) K. The Halpha wings, C IV, and X-rays all showed a short-lived and compact (3'' x 3'') brightening in a location near the leading sunspot. At this location, small-scale changes in the magnetic field were observed from about 2 hr before to about 6 hr afterthe miniflare. Only very small velocities seem to have been associated with most of the event in Halpha. The data are consistent with shortand dense loops at temperatures above 10(7) K which lost a large fraction of their energy via downward conduction through transition regions at the footpoints. Several secondary events appear to have been triggered by the miniflare along an arch filament which itself was not greatly affected. A number of much less energetic (10(25)-10(26) erg) events preceded and followed the mini-flare. One of these occurred 11 minutes after the mini-flare and displayed a highly Doppler-shifted signature from the foot-point of a C IV arch. This arch delineates the connection that existed between the location of the mini-flare and the location of secondary events triggered by the flare.

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Documento generato il 04/12/20 alle ore 21:47:00