INVESTIGADORES
MANDRINI Cristina Hemilse
artículos
Título:
Determining the solar source of a magnetic cloud using a 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: Berlín; 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 region cannot be observed due to the bright emission from the
flare itself. However, spectroscopic data 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
on the 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 velocity measurements we could extract
information on the core dimming region, as well as on remote dimmings.
The purpose of this paper is to determine more accurately the magnetic
flux of the solar source region, potentially involved in the ejection,
through a new technique. The results 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 EUV
Imaging Spectrometer to estimate the Doppler velocity in the active
region and its surroundings before 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 Imager magnetogram 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 and compared to the magnetic cloud flux. This new
method provides a more accurate flux determination in the solar source
region.