Three-dimensional stereoscopic analysis of a coronal mass ejection and comparison with UV spectroscopic data

Journal Article · Sun Jul 20 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/790/1/25· OSTI ID:22365628

Susino, Roberto; Bemporad, Alessandro ^[1]; Dolei, Sergio ^[2]

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1. INAF-Osservatorio Astrofisico di Torino, via Osservatorio 20, I-10025 Pino Torinese (Italy)
2. INAF-Osservatorio Astrofisico di Catania, via S. Sofia 78, I-95123 Catania (Italy)

A three-dimensional (3D) reconstruction of the 2007 May 20 partial-halo coronal mass ejection (CME) has been made using STEREO/EUVI and STEREO/COR1 coronagraphic images. The trajectory and kinematics of the erupting filament have been derived from Extreme Ultraviolet Imager (EUVI) image pairs with the 'tie-pointing' triangulation technique, while the polarization ratio technique has been applied to COR1 data to determine the average position and depth of the CME front along the line of sight. This 3D geometrical information has been combined for the first time with spectroscopic measurements of the O VI λλ1031.91, 1037.61 line profiles made with the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory. Comparison between the prominence trajectory extrapolated at the altitude of UVCS observations and the core transit time measured from UVCS data made possible a firm identification of the CME core observed in white light and UV with the prominence plasma expelled during the CME. Results on the 3D structure of the CME front have been used to calculate synthetic spectral profiles of the O VI λ1031.91 line expected along the UVCS slit, in an attempt to reproduce the measured line widths. Observed line widths can be reproduced within the uncertainties only in the peripheral part of the CME front; at the front center, where the distance of the emitting plasma from the plane of the sky is greater, synthetic widths turn out to be ∼25% lower than the measured ones. This provides strong evidence of line broadening due to plasma heating mechanisms in addition to bulk expansion of the emitting volume.

• OSTI ID: 22365628
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 790; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPARATIVE EVALUATIONS
EXPANSION
EXTREME ULTRAVIOLET RADIATION
IMAGES
LINE BROADENING
LINE WIDTHS
MASS
PLASMA
PLASMA HEATING
POLARIZATION
SPECTROMETERS
STELLAR CORONAE
SUN
THREE-DIMENSIONAL CALCULATIONS
VISIBLE RADIATION