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"Solar Coronal Mass Ejections: What goes up, must come down?," Friday, April 17, 12:00pm, MH 606
Damian Christian, California State University, Northridge
ABSTRACT: I will review some of the outstanding issues regarding heating the Sun’s corona and present our new multi-wavelength study of a failed coronal mass ejection. I obtained H-alpha high spatial and time resolution observations of the upper solar chromosphere and supplemented these with multi-wavelength observations from the Solar Dynamic Observatory (SDO) and the Hinode ExtremeUltraviolet Imaging Spectrometer (EIS). The H-alpha observations were conducted on 11 February 2012 with the Hydrogen-Alpha Rapid Dynamics Camera (HARDcam) instrument at the National Solar Observatory's Dunn Solar Telescope. Our H-alpha observations found large downflows of chromospheric material returning from coronal heights following a failed prominence eruption. We have detected several large condensations (``blobs'') returning to the solar surface at velocities of ~200 km/s in both H-alpha and several SDO AIA band passes. The average derived size of these ``blobs'' in H-alpha is 500 by 3000 km^2 in the directions perpendicular and parallel to the direction of travel, respectively. A comparison of our ``blob" widths to those found from coronal rain, indicate there are additional smaller, unresolved ``blobs" in agreement with previous studies and recent numerical simulations. Our observed velocities and decelerations of the ``blobs'' in both H-alpha and SDO bands are less than those expected for gravitational free-fall and imply additional magnetic or gas pressure impeding the flow. We derived a kinetic energy ~2 orders of magnitude lower for the main eruption than a typical CME, which may explain its partial nature. Detailed studies of failed CMEs and other phenomenon will allow further constraints on the coronal magnetic field and in the larger problem of coronal heating.