Working Group 3: Coronal X-ray and gamma-ray sources, and their relation to CMEs and SEPs

Working Group 3: Coronal X-ray and gamma-ray sources, and their relation to CMEs and SEPs (team leader: Alexander Warmuth) Abundances (Share, Dennis) Coronal HXR sources (Glesener, Krucker) Source sizes and energetics (Warmuth, Dennis) Relationship to CMEs (Gallagher, Milligan) Interplanetary electrons (Klassen, Vocks)

Fits to the 1981 April 27 flare showing the total fit, bremsstrahlung, direct interaction (i.e. accelerated p and α on ambient elements), inverse interaction (i.e. heavy ions on ambient elements), α4he, and 0.511/2.223 MeV line components and Compton-scattered 2.2 MeV line. We show fits with the total model (resolved + unresolved lines) and resolved-line model only. Gerry Share

In order to estimate the ambient abundances (normalized to O) for the flare we use the parameters for the best fitting α/p ratio and spectral index consistent with a photospheric He/O. C/O ratio consistent with photospheric and coronal values; N is slightly higher; Ne/O is ~12% (note this is lower the value adopted by Ramaty et al.,) the low FIP elements have abundances between photospheric and coronal. The abundances determined from fits with and without the unresolved component are similar. Gerry Share

Contributions to MESSENGER XRS Spectrum CHIANTI v. 5.2 Brian Dennis

Messenger XRS Abundances Flare Peak Times FIP (ev) Brian Dennis

Abundances important for obtaining correct thermal parameters often between photospheric and coronal abundance potential for distinguishing evaporated chromospheric material from plasma heated directly in the corona Future work: Get abundances in photosphere from gamma-ray spectroscopy SXR spectroscopy with Messenger/XRS and CORONAS-PHOTON/SphinX

RHESSI observations Statistical study of partially occulted flares (Krucker & Lin 2008): ~90% of flares show non-thermal emission from corona often seen: rarely seen: HXR emission from flare loop above-loop-top source (Masuda flare) Säm Krucker

Lindsay Glesener

RHESSI imaging: HXR peak STEREO B during HXR peak flare ribbons in blue and red HXR peak time; loop? above flare arcade? thermal loops are below rare case of above-the-loop-top source (along flare arcade)? low ambient density before flare. Säm Krucker

COR1, EUVI, RHESSI rough location of HXR sources flare site HXR sources Is coronal HXR emission related to reconnection outflow/termination shock? dimming Säm Krucker

Coronal sources Nonthermal sources with fast time variation Mostly cospatial or partly overlapping with thermal sources, some above-the-looptop (Masuda-type) Association of late-phase nonthermal source with CME current sheet? Future work: Continue analysis of partly occulted flares Use multi-view observations from STEREO

C flare, simple geometry, all areas CLEAN uniform CLEAN natural VIS_FWD MEM_NJIT Alexander Warmuth

Thermal volumes direct & indirect method 263 data pairs Alexander Warmuth

Instantaneous thermal energy SXR & HXR 17 flares, 2192 spectra Alexander Warmuth

Thermal and nonthermal total energies Alexander Warmuth

09/08/08 RHESSI Workshop Potsdam 18 Brian Dennis

Source sizes and energetics Comparing different methods for source size determination give error estimates Thermal and nonthermal energy comparable Total radiated energy = 10 x thermal energy (SXR) = 100 x radiated energy (SXR) = CME kinetic energy Future work: Compare/evaluate different methods for source size determination Continue to improve spectroscopy

April 21, 2002 ~ December 17, 2006 Peter Gallagher

Conclusions Known knowns: Well characterized pre- and post eruption loop kinematics. Good idea of CME kinematics at 3-30RS. Known unknowns: CME kinematics at 1-3RS. What are forces governing loop and CME motions? Where do they act and over what length-scale? When do they act and over what time-scale? Unknown unknowns: Anyone seen a current sheet lately? Is there a theoretical alternative? Peter Gallagher

Ryan Milligan

Flare CME relationship HXR observations can be used to test CME models Good kinematics of CME and rising arcade potential observation of recoil response of coronal HXR source to CME Future work: Need for CME kinematics at 1-3 Rs Derive forces acting on CME from kinematics

Andreas Klassen

Christian Vocks

Interplanetary electrons Strong observational evidence for nearly scatter-free propagation Consistent with simulations Spike events: release delayed by ~10 min from type III Future work: Study relationship of spikes with HXRs & jets Comparison with magnetospheric spike events Refine numerical models

Overall conclusion We have discussed several seemingly unconnected issues in WG 3 However: sometimes previously unnoticed connections have turned up Thus: Try to stay informed on as many diverse RHESSIrelated issues as possible! Something you have not considered before might turn up that can be helpful for your pet project.