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Markus J. Aschwanden Submitted: 20071101 09:14
We present the first triangulation and 3D reconstruction of coronal loops,
using the EUVI telescopes of the two STEREO A and B spacecraft.
This first triangulation of coronal loops is performed in an active region,
observed with STEREO A and B on 2007 May 9 with a spacecraft separation
angle of α _sep=7.3 deg, at a wavelength of 171 Å .
We identify 30 loop structures (7 complete loops and 23 partial segments)
and compute their 3D coordinates [x, y, z], [the full 3D coordinates
are available as an electronic file]. We quantify the height range,
the stereoscopic height measurement errors, the loop plane inclination angles,
and the coplanarity and circularity of the analyzed loops.
The background of the active region shows also ``moss''
features, for which we determine a mean height of h_{moss} ~ 4 Mm.
The knowledge of the exact 3D geometry of a loop with respect to the observers
lineofsight has important consequences for determining the correct vertical
density scale height (used in hydrostatic models), the aspect angle of
loop crosssections (used in inferring electron densities from optically thin
emission measures), the absolute flow speeds (used in siphon flow models),
the correct loop length (used in loop scaling laws), as well as the 3D vectors
of the coronal magnetic field (used in testing theoretical magnetic field
extrapolation models). The hydrodynamic and magnetic mo
Authors: Markus J. Aschwanden, JeanPierre Wuelser, Nariaki Nitta, Jim Lemen
Projects: STEREO

Publication Status: ApJ (in preparation)
Last Modified: 20071101 09:14


