UV Spectroscopy of CME Currrent Sheets John Raymond Angela Ciaravella Silvio Giordano Dave Webb Overview Lin & Forbes Model Reconnection occurs between the flare loops and the CME core. It converts magnetic energy to heat, Kinetic energy and energetic particles. It releases the overlying magnetic arches, allowing CME to escape. It creates or adds to a twisted magnetic flux rope. It is crucial to areas of astrophysics, such as accretion disks. Current Sheet Models Petschek Turbulent Lazarian & Vishniac Tajima & Shibata Vrnak Diagnostics Temperature e.g., [Fe XVIII], [Fe XXI], X-rays Density Combine emission measure with column density Thickness Projection effects? Turbulent Speed Line widths (correct for thermal speed) Reconnection rate Inflow/outflow speeds; blobs, filaments (Yokoyama; Lin et al.) Innes et al Apr 21, TRACE 195 [Fe XVIII] -- 6 x 10 6 K Lower T lines UV: High temperature feature between flare loops and CME CME Core Post-flare Arcade Reconnection Current Sheets Magnetic Reconnection is poorly understood. It heats and accelerates gas, produces energetic particles. Spectra determine electron and ion temperatures, densities, turbulence. Ciaravella et al. November 4, 2003 CME Current Sheet Ciaravella & Raymond 302 262 228 1.66 R Current Sheet 2003 November 4 CS: Images [Fe XVIII] emission begins ~ 8 min after the CME peak move by ~ 4 south in 2.5 h narrows and becomes constant Si XII emission starts about 2h later: implies cooling OVI and CIII are patchy: cold plasmoids are detected offset from hot emission CS in MLSO-MK4 provides N e time (UT) PA Fe XVIII Si XII logT EM N e n e d ph/(cm 2 sec sr) cm cm cm -3 R 17:20-19: :27-21: :06-21: :03-22: :19-00: :42-01: * 0.21* 03:29-04: MLSO Mark IV pB [Fe XVIII] Temperature and density in the CS decrease with time 400 km/s 5 x g Traces back to C III blob Do Blob motions give Alfvn speed? Sometimes. Bemporad 2008 Turbulent (?) Line Widths vs. Time T ION ~130 km/s Landi et al Cartwheel CME Landi et al. -- Cartwheel CME Landi et al. Effective Temperature from Fe XII and Fe XV linewidths ~ 110 km/s FWHM ~ 85 km/s White Light rays: 03/10/04 Ciaravella et al. MLSO + LASCO Many hours O VI displaced South Si XII broad O VI Fe XVIII Si XII [Fe XVIII] offset from O VI; Si XII is diffuse Sep 21, 2001 [Fe XVIII] intensity poorly correlated with CME speed [Fe XVIII] intensity poorly correlated with height Observing bias? Summary Temperatures; 3 to 8 to 15 MK Slow cooling Densities: 4 to 10 x10 7 at 1.7 R SUN Thickness: 0.01 to 0.1 R SUN projection effects not all that bad Turbulent speed: ~ 100 km/s, slowly decreasing Reconnection rate: 0.01 to 0.1