IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
The solar source of a magnetic cloud using velocity difference technique
Autor/es:
HARRA L.K.; MANDRINI C.H.; DASSO S.; GULISANO A.M.; STEED K.; IMADA S.
Revista:
SOLAR PHYSICS
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2011 vol. 268 p. 213 - 230
ISSN:
0038-0938
Resumen:
For large eruptions on the Sun, it is often a problem that the core dimming regioncannot be observed due to the bright emission from the flare itself. However, spectroscopicdata can provide the missing information through the measurement of Doppler velocities.In this paper we analyse the well-studied flare and coronal mass ejection that erupted onthe Sun on 13 December 2006 and reached the Earth on 14 December 2006. In this example,although the imaging data were saturated at the flare site itself, by using velocitymeasurements we could extract information on the core dimming region, as well as on remotedimmings. The purpose of this paper is to determine more accurately the magnetic fluxof the solar source region, potentially involved in the ejection, through a new technique. Theresults of its application are compared to the flux in the magnetic cloud observed at 1 AU,as a way to check the reliability of this technique. We analysed data from the Hinode EUVImaging Spectrometer to estimate the Doppler velocity in the active region and its surroundingsbefore and after the event. This allowed us to determine a Doppler velocity ?difference?image. We used the velocity difference image overlayed on a Michelson Doppler Imagermagnetogram to identify the regions in which the blue shifts were more prominent after the event; the magnetic flux in these regions was used as a proxy for the ejected flux andcompared to the magnetic cloud flux. This new method provides a more accurate flux determinationin the solar source region.