The Significance of the Influence of the CME Deflection in Interplanetary Space on the CME Arrival at Earth

Abstract

As one of the most violent astrophysical phenomena, coronal mass ejections (CMEs) have strong potential space weather effects. However, not all Earth-directed CMEs encounter the Earth and produce geo-effects. One reason is the deflected propagation of CMEs in interplanetary space. Although there have been several case studies clearly showing such deflections, it has not yet been statistically assessed how significantly the deflected propagation would influence the CME’s arrival at Earth. We develop an integrated CME-arrival forecasting (iCAF) system, assembling the modules of CME detection, three-dimensional (3D) parameter derivation, and trajectory reconstruction to predict whether or not a CME arrives at Earth, and we assess the deflection influence on the CME-arrival forecasting. The performance of iCAF is tested by comparing the two-dimensional (2D) parameters with those in the Coordinated Data Analysis Workshop (CDAW) Data Center catalog, comparing the 3D parameters with those of the gradual cylindrical shell model, and estimating the success rate of the CME Earth-arrival predictions. It is found that the 2D parameters provided by iCAF and the CDAW catalog are consistent with each other, and the 3D parameters derived by the ice cream cone model based on single-view observations are acceptable. The success rate of the CME-arrival predictions by iCAF with deflection considered is about 82%, which is 19% higher than that without deflection, indicating the importance of the CME deflection for providing a reliable forecasting. Furthermore, iCAF is a worthwhile project since it is a completely automatic system with deflection taken into account.

An operational solar wind prediction system transitioning fundamental science to operations

“…Hough transform is an image processing method and can identify lines or other shapes by voting procedure. Zhuan et al (2017) also used this algorithm to detect and identify CMEs automatically. A comparison with the manual CME catalog in May 2011 at the Coordinated Data Analysis Workshop (CDAW) Data Center (Gopalswamy et al, 2009) reveals that the detection rate of major CMEs is 95% when using this algorithm (Zhuan et al, 2017).…”

“…Zhuan et al (2017) also used this algorithm to detect and identify CMEs automatically. A comparison with the manual CME catalog in May 2011 at the Coordinated Data Analysis Workshop (CDAW) Data Center (Gopalswamy et al, 2009) reveals that the detection rate of major CMEs is 95% when using this algorithm (Zhuan et al, 2017). Therefore, we adopt in our operational system the same algorithm as in Zhuan et al (2017).…”

“…A comparison with the manual CME catalog in May 2011 at the Coordinated Data Analysis Workshop (CDAW) Data Center (Gopalswamy et al, 2009) reveals that the detection rate of major CMEs is 95% when using this algorithm (Zhuan et al, 2017). Therefore, we adopt in our operational system the same algorithm as in Zhuan et al (2017). It runs in real-time and provides a rapid detection results as one of the important references for our forecaster.…”

Large non-radial propagation of a coronal mass ejection on 2011 January 24

“…Coronal mass ejections (CMEs) are the main drivers of geomagnetic storms. The study of their direction of propagation throughout both the lower solar corona and interplanetary medium is a crucial first step to estimate their potential geo-effectiveness (see, e.g., Zhuang et al, 2017). The characterization of the coronal environment along the CME's early development is of utmost importance for finding potential structures that could influence the CMEs trajectory and hence make an assessment of the likelihood of an Earth encounter.…”

Three-Dimensional Parameters of the Earth-Impacting CMEs Based on the GCS Model

“…In total, the GCS model itself also contributes to errors. Recently, some new methods have been developed that aim to eliminate model defects or manual errors, which can be used to estimate a CME's propagation (e.g., CORSET3D [65], iCAF [67] and ELEvoHI [68]).…”