Microwave emission as a proxy of CME speed in ICME forecasting by Carolina Salas Matamoros, Ludwig Klein and Gerard Trottet9 May 2017, 11:07 UTC
Coronal Mass Ejections (CMEs) are one type of interplanetary structure that mostly affect the geomagnetic field (e.g. Gonzalez and Tsurutani, 1987; Zhang et al, 2007). These structures are observed and studied through coronagraphic images. The basic limitation of the coronagraph is that it shows the corona only in the plane of the sky, and blocks by necessity the view on the solar disk. Thus, the projection effect in the kinematic properties of a CME increases as the propagation direction of the CME approaches the line-of-sight of the spacecraft. So, the measurements of the propagation speed in this case are not accessible to coronagraphic observations, only the expansion speed.
We explore if microwave emission can be used as an alternative for coronagraphic proxies for CME propagation speed. Also, we use the microwave proxy, together with the empirical interplanetary acceleration model devised by Gopalswamy et al. (2001), to predict the CME arrival time at Earth of 11 Earth-directed CMEs.
We carefully select a data set of CMEs observed at the limb by LASCO coronagraph on board the SoHO spacecraft to reduce the projection effect. We assume that the measured projected speed is the outward CME propagation speed. Also, we identify the ...