Pseudo-automatic Determination of Coronal Mass Ejections’ Kinematics in 3D

Abstract

Coronal mass ejection (CME) events are among the main drivers of geomagnetic disturbances, and hence play a central role in the Sun–Earth system. Their monitoring and, in particular, the determination of their speed and direction of propagation are key issues for the forecasting of space weather near to Earth. We have implemented a method to track CME events in three dimensions by combining triangulation and tie-pointing analysis with a supervised computer vision algorithm. This novel approach does not rely on any geometric constraint, and eliminates the need for visual identification of the CME boundaries. We applied our method to 17 CME events observed simultaneously by the twin Solar Terrestrial Relations Observatory (STEREO) COR2 coronagraph imagers from 2008 December to 2011 November in order to obtain their 3D kinematical characterization (i.e., the velocity vector) along with their morphological properties. About ten of these events have already been analyzed using other methodologies. In these cases, we carried out a thorough comparison with our results and found that, in spite of the different nature and spatial coverage range of the other methods with respect to CORSET3D, the majority of the results agree. We found, however, that three events exhibited discrepancies in the magnitude of the velocity vector, four in the longitudinal direction of propagation, and in only one case was there a discrepancy in latitude. The discrepancies appeared in those cases where quasi-simultaneous, quasi-co-located events were observed in the coronagraphs’ fields of view.

How Reliable Are the Properties of Coronal Mass Ejections Measured from a Single Viewpoint?

“…The overall performance of the supervised computer vision algorithm CORSET as well as the direct comparison with measurements from other catalogs have already been addressed and briefly discussed in previous works (see, e.g., Goussies et al 2010;Braga et al 2013Braga et al , 2017. However, the number of events analyzed in these works falls short of meaningful statistics to allow us to draw a general picture of the caveats and benefits of such a technique.…”

Predicting the Time of Arrival of Coronal Mass Ejections at Earth From Heliospheric Imaging Observations

“…Triangulation is yet another methodology to derive the CME kinematics. In this case, co‐temporal observations are needed, e.g., from the twin heliospheric imagers or coronagraphs onboard STEREO (e.g., Braga et al., 2017; Y. Liu et al., 2010, 2011; Liewer et al., 2011). This methodology normally requires selection and tracking of particular point‐like features in each viewpoint.…”

First Determination of 2D Speed Distribution within the Bodies of Coronal Mass Ejections with Cross-correlation Analysis

“…Feng et al (2015a) provided a method to investigate the CME kinematics via determining the radial mass transport process throughout the entire CME, which is capable of the estimation of the radial flow speed inside the CME. Braga et al (2017) used the CORSET3D to determine the tie-points along the CME front automatically in three-dimensional (3D) space and derived the average two-dimensional (2D) speed of CMEs' fronts in the Stonyhurst coordinate system. Compared with these studies, all of these results have never shown the 2D kinetic and potential energy distributions of CMEs.…”