110 likes | 239 Views
A flare compilation. Lots of people including Louise Harra, Lidia van Driel Gesztelyi, Chris Goff, Sarah Matthews, Len Culhane, Cristina Mandrini, Pascal Demoulin, Lyndsay Fletcher. 15 Jul 02 – two filament eruptions and a couple of CMEs. Spectroscopic evidence for break-out.
E N D
A flare compilation • Lots of people including Louise Harra, Lidia van Driel Gesztelyi, Chris Goff, Sarah Matthews, Len Culhane, Cristina Mandrini, Pascal Demoulin, Lyndsay Fletcher
Spectroscopic evidence for break-out • In contrast to the standard model reconnection starts high in the corona. • Evidence has been found in the form of remote brightenings (and flows) prior to the impulsive phase. Gary and Moore., 2004, Harra et al. 2005 Sterling and Moore
Spatially resolved evaporation has been observed in various cases now e.g .Brosius and Phillips (2004) with velocities 10s km/s and del Zanna et al (2005) with velocities reaching 140 km/s. Following filament eruption Harra et al., 2005 Pre-eruption stage
CDS SOHO/CDS slit Position Fe XIX Doppler velocity Fe XIX intensity Flux rope Vl < 0 Flux rope Vl > 0 Flare loops Flare loops Time 13:0015:00 Time Synthetic slit image made of TRACE data TRACE EUV image SOHO/CDS observations
rotated and tilted to event location flare time disc centre view Magnetic modelling view tilted to show arcade orientation Magnetic field lines extrapolated in the linear force-free approximation (=0.015 Mm-1) using a SOHO/MDI magnetic field map on 14 April in order to determine the 3-D spatial orientation of the flare loop and deduce the direction of plasma flows from the Doppler data.
position Fe XIX Doppler velocity Vl<0 Vl>0 time Combining modelling results with CDS Doppler shift S leg points away from us - Red-shifted in CDS N leg points towards us - Blue-shifted in CDS Plasma is flowing down along both legs of the flare loops
RHESSI observations: Moving (rising) coronal X-ray source RHESSI 10-15 keV contours (made with PIXON) over TRACE images show a rising coronal X-ray source. Images made in the 5-10 keV and 15-20 keV ranges show very similar motion pattern. v≈60 km/s Looptop source Rising coronal source
Erupting filament (TRACE) Rising X-ray source (RHESSI) Height-time plots - low corona CDS obser- vation • Height - time plot of the lifting flux rope as seen by TRACE. • The cross in the red circle represents the leading edge of the flux rope as seen by CDS. • Below the best-fit lines are data points from the coronal hard X-ray source. • HXR RHESSI light curve between 5-50 keV.
Height-time plots - TRACE & C2 Height-time plot of CME leading and trailing edges in LASCO/C2 images Height-time plot of lifting filament in TRACE images vCME ~ 120 km s-1 An exponential growth makes the link between the two curves, while neither the linear nor the polynomial fit can reach the required height by the C2 appearance time of the CME.
Blabla blabla Blab l Height-time plot, low corona Exponential growth Height-time plot, high corona EUV flux rope v~45-75 km/s LASCO/C2 v~120 km/s LASCO/C2 RHESSI source ~60 km/s TRACE v~60 km/s • New evidence for flux rope structure of an erupting filament • Linking a rising RHESSI coronal source to the erupting filament • New evidence for exponential growth of CMEs in the low corona - result of kink instability? • Results consistent with down-flows of hot plasma along both loop legs. Contour: RHESSI 10-15 keV SOHO/CDS slit position Fe XIX Doppler velocity Flux rope Vl<0 + Vl>0 Cooling loops magnetic extrapolation 3-D flare loop orientation TRACE EUV image A&A 434, 761 (2005) time