IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
3D Temperatures and Densities of the Solar Corona Via Multi-Spacecraft EUV Tomography: Analysis of Prominence Cavities.
Autor/es:
VÁSQUEZ, ALBERTO M.; FRAZIN, RICHARD A.; KAMALABADI, FARZAD
Revista:
SOLAR PHYSICS
Editorial:
Springer
Referencias:
Lugar: New York, EEUU; Año: 2008
ISSN:
0038-0938
Resumen:
Three-dimensional (3D) tomographic analysis of extreme ultraviolet (EUV)
images is used to place empirical constraints on the coronas
temperature and density structure. The input data are images taken by
the EUVI instrument on STEREO A and B spacecraft for Carrington Rotation
2069 (16 April to 13 May 2008). While the reconstructions are global, we
demonstrate the capabilities of this method by examining specific
structures in detail. Of particular importance are the results for
coronal cavities and the surrounding helmet streamers, which our method
allows to be analyzed without projection effects for the first time.
During this rotation, both the northern and southern hemispheres
exhibited stable polar crown filaments with overlying EUV cavities.
These filaments and cavities were too low-lying to be well observed in
white-light coronagraphs. Furthermore, due to projection effects, these
cavities were not clearly discernible above the limb in EUV images, thus
tomography offers the only option to study their plasma properties
quantitatively. It is shown that, when compared to the surrounding
helmet material, these cavities have lower densities (about 30%, on
average) and broader local differential emission measures that are
shifted to higher temperatures than the surrounding streamer plasma.