Reconstructing Solar Wind Inhomogeneous Structures From Stereoscopic Observations in White Light: Solar Wind Transients in 3-D

Abstract

White-light images from Heliospheric Imager-1 (HI1) onboard the Solar Terrestrial Relations Observatory (STEREO) provide two-dimensional (2-D) global views of solar wind transients traveling in the inner heliosphere from two perspectives. How to retrieve the hidden three-dimensional (3-D) features of the transients from these 2-D images is intriguing but challenging. In our previous work (Li et al., 2018, https://doi.org/10.1029/2018JA025485), a "correlation-aided" method is developed to recognize the solar wind transients propagating along the Sun-Earth line based on simultaneous HI1 images from two STEREO spacecraft. Here the method is extended from the Sun-Earth line to the whole 3-D space to reconstruct the solar wind transients in the common field of view of STEREO HI1 cameras. We demonstrate the capability of the method by showing the 3-D shapes and propagation directions of a coronal mass ejection (CME) and three small-scale blobs during 3-4 April 2010. Comparing with some forward modeling methods, we found our method reliable in terms of the position, angular width, and propagation direction. Based on our 3-D reconstruction result, an angular distorted, nearly north-south oriented CME on 3 April 2010 is revealed, manifesting the complexity of a CME's 3-D structure.