Three-dimensional Reconstruction of Coronal Mass Ejections by CORAR Technique through Different Stereoscopic Angle of STEREO Twin Spacecraft

TL;DR

This study evaluates the CORAR stereoscopic reconstruction method for CMEs using different STEREO angles, identifying optimal angles for accurate 3D reconstruction and proposing corrections for directional deviations.

Contribution

It analyzes how the separation angle affects CME reconstruction accuracy with CORAR and suggests optimal angles and correction formulas for improved results.

Findings

Optimal separation angle around 150° for CME reconstruction.

Best angles between 120° and 150° considering collinear effects.

CORAR-derived CME parameters are consistent with existing catalogs, with some directional deviations.

Abstract

Recently, we developed the Correlation-Aided Reconstruction (CORAR) method to reconstruct solar wind inhomogeneous structures, or transients, using dual-view white-light images (Li et al. 2020; Li et al. 2018). This method is proved to be useful for studying the morphological and dynamical properties of transients like blobs and coronal mass ejection (CME), but the accuracy of reconstruction may be affected by the separation angle between the two spacecraft (Lyu et al. 2020). Based on the dual-view CME events from the Heliospheric Imager CME Join Catalogue (HIJoinCAT) in the HELCATS (Heliospheric Cataloguing, Analysis and Techniques Service) project, we study the quality of the CME reconstruction by the CORAR method under different STEREO stereoscopic angles. We find that when the separation angle of spacecraft is around 150{\deg}, most CME events can be well reconstructed. If the collinear effect is considered, the optimal separation angle should locate between 120{\deg} and 150{\deg}. Compared with the CME direction given in the Heliospheric Imager Geometrical Catalogue (HIGeoCAT) from HELCATS, the CME parameters obtained by the CORAR method are reasonable. However, the CORAR-obtained directions have deviations towards the meridian plane in longitude, and towards the equatorial plane in latitude. An empirical formula is proposed to correct these deviations. This study provides the basis for the spacecraft configuration of our recently proposed Solar Ring mission concept (Wang et al. 2020b).