Science Seminars

Coronal Mass Ejections and Space Weather

Speaker: David Webb (Boston College)
Date: Thursday, Jan 31, 2013
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

What are Coronal Mass Ejections (CMEs) and why are they important? CMEs have typically been observed in white light near the Sun by coronagraphs, recently those on the SOHO LASCO and STEREO missions. I will review our current knowledge of CMEs including their coronal and heliospheric properties. I will discuss their importance for space weather, including studies of the signatures of CMEs in the solar wind and the drivers of geomagnetic storms at Earth. I will describe some recent work on structures within CMEs, such as magnetic clouds/flux ropes and current sheets. In the last decade two heliospheric imagers have added wide-field viewing capabilities of CMEs in the heliosphere, the Solar Mass Ejection Imager (SMEI) in Earth orbit from 2003-2011 and the SECCHI Heliospheric Imagers (HIs) on STEREO in solar 1 AU orbits since early 2007. I will conclude with examples of the imaging and tracking of CMEs in the heliosphere, and the use of a new STEREO SECCHI processing pipeline. This system permits heliospheric tracking and quantitative measurements of CME structures and disconnection events. Already these results are providing data on the cycling of solar magnetic flux through the heliosphere.