What is the role of flare ribbon structure on CME speeds?
Abstract
Coronal mass ejections (CMEs) are the primary drivers of severe space weather disturbances, but remain poorly understood. Hence, efforts to characterize and predict their dynamics are ongoing. Many CMEs are associated with solar flares, and, in particular, flare ribbons, which are bright bands of strongly enhanced emission originating above magnetized areas of the photosphere. As a solar eruption progresses, these ribbons typically move across areas that contain fluxes of order 1021 Mx or more. The rate at which the ribbons sweep across photospheric flux is thought to correspond to the rate of coronal magnetic reconnection. Previous studies found significant correlations between CME speeds and the total amount of flux swept by flare ribbons. Here, we investigate relationships between CME speeds and spatial moments of their source-region photospheric magnetic fields and flare ribbons, including spatial moments of: (i) magnetic flux in the source region; (ii) signed and (iii) unsigned magnetic flux within ribbon areas; and (iv) binary maps ribbon areas. Our sample consists of N = 75 CMEs in the SOHO/LASCO CME catalog that were manually associated with flare ribbons identified in SDO/AIA data. Vector magnetograms obtained by SDO/HMI were used in our calculations of source-region magnetic properties. We confirm prior results that correlations between CME speeds and total magnetic fluxes swept by flare ribbons are statistically significant. We also find that spatial moments of ribbon magnetic fields are also significantly correlated with CME speeds.
- Publication:
-
American Astronomical Society Meeting Abstracts #234
- Pub Date:
- June 2019
- Bibcode:
- 2019AAS...23411201W