Establish the three-dimensional geometry of the observed coronal structures

Determine the true three-dimensional geometry of the coronal loop complexes and establish whether the apparent triple structure observed along the line of sight represents three physically distinct structures rather than a projection effect.

Background

The event was observed primarily in two-dimensional extreme-ultraviolet and hard X-ray images, with only a small separation between the available viewing directions. The STEREO-A perspective did not resolve the geometrical ambiguity, because several loop complexes could appear as a triple structure when projected along the line of sight.

Resolving this issue is necessary for interpreting the spatial relationships among the non-thermal and thermal X-ray sources and for determining whether the inferred source locations correspond to distinct physical structures. The authors indicate that stereoscopic observations and triangulation would be needed to obtain their true three-dimensional positions.