Low-Frequency Type-II Radio Detections and Coronagraph Data Employed to Describe and Forecast the Propagation of 71 CMEs/Shocks
Abstract
Motivated by improving predictions of arrival times at Earth of shocks driven by coronal mass ejections (CMEs), we have analyzed 71 Earth-directed events in different stages of their propagation. The study is primarily based on approximated locations of interplanetary (IP) shocks derived from Type-II radio emissions detected by the Wind/WAVES experiment during 1997 - 2007. Distance-time diagrams resulting from the combination of white-light corona, IP Type-II radio, and in-situ data lead to the formulation of descriptive profiles of each CME's journey toward Earth. Furthermore, two different methods for tracking and predicting the location of CME-driven IP shocks are presented. The linear method, solely based on Wind/WAVES data, arises after key modifications to a pre-existing technique that linearly projects the drifting low-frequency Type-II emissions to 1 AU. This upgraded method improves forecasts of shock-arrival times by almost 50 %. The second predictive method is proposed on the basis of information derived from the descriptive profiles and relies on a single CME height-time point and on low-frequency Type-II radio emissions to obtain an approximate value of the shock arrival time at Earth. In addition, we discuss results on CME-radio emission associations, characteristics of IP propagation, and the relative success of the forecasting methods.
- Publication:
-
Solar Physics
- Pub Date:
- September 2015
- DOI:
- 10.1007/s11207-015-0776-y
- arXiv:
- arXiv:1505.01730
- Bibcode:
- 2015SoPh..290.2455C
- Keywords:
-
- Coronal mass ejections;
- initiation and propagation;
- Radio bursts;
- type II;
- Waves;
- shock;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Solar Physics