Coronal mass ejection (CME) is the large scale magnetized plasmoid ejected from the Sun, which brings huge amount of magnetic flux and plasma into interplanetary space. An earthward CME will interact with the magnetosphere of the Earth and invokes the substorm and the other phenomena of the space weather as it approaches to the Earth. The 2-dimansional data provided by the current observational techniques cannot describe the true magnetic structure and the plasma distribution of CMEs comprehensively. We need to look into the 3-dimensional structure and the associated three components of CME speeds in order to predict the time when an ICME reaches the Earth and the potential consequent impact on the Earth and the nearby environment. In this paper, 3D reconstruction of CME based on existing imaging observations are introduced, including two kinds of reconstruction methods based on coronagraph data and heliospheric imaging data , as well as 3D reconstruction for the CME-drive shock that is highly correlated to the CME imaging reconstruction. Each method shows apparent advantages in dealing with specific events, but its weakness and necessary constrains to its applications exist as well. Results obtained via various methods are compared in this work, and we found that CME velocities and moving directions deduced from these methods are fairly close to one another, which shows high reliability of these methods. Then, an experience-based CME arrival model is introduced, and the time required for CME to reach 1AU position is predicted using reconstructed 3D velocity.Finally, the hot topics related to the 3-dimanesional reconstruction of CME (ICME) and the relevant development in reconstructing methods are also discussed.
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