Optimal Stereoscopic Angle for Reconstructing Solar Wind Inhomogeneous Structures

This paper is aimed at finding the best separation angle between spacecraft for the three-dimensional reconstruction of solar-wind inhomogeneous structures by the CORrelation-Aided Reconstruction(CORAR) method. The analysis is based on the dual-point heliospheric observations from the STEREO HI-1 cameras. We produced synthetic HI-1 white-light images containing artificial blob-like structures in different positions in the common field of view of the two HI-1 cameras and reconstruct the structures with CORAR method. The distributions of performance levels of the reconstruction for spacecraft separation of $60^{\circ}$, $90^{\circ}$, $120^{\circ}$ and $150^{\circ}$ are obtained. It is found that when the separation angle is $120^{\circ}$, the performance of the reconstruction is the best and the separation angle of $90^{\circ}$ is the next. A brief discussion of the results are given as well. Based on this study, we suggest the optimal layout scheme of the recently proposed Solar Ring mission, which is designed to routinely observe the Sun and the inner heliosphere from multiple perspectives in the ecliptic plane.