caa a22 4500 445816430 CHVBK 20180317145229.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s11214-011-9801-0 doi (NATIONALLICENCE)springer-10.1007/s11214-011-9801-0 Lin R. Physics Department and Space Sciences Laboratory, UC Berkeley, 94720, Berkeley, CA, USA aut Energy Release and Particle Acceleration in Flares: Summary and Future Prospects [Elektronische Daten] [R. Lin] RHESSI measurements relevant to the fundamental processes of energy release and particle acceleration in flares are summarized. RHESSI's precise measurements of hard X-ray continuum spectra enable model-independent deconvolution to obtain the parent electron spectrum. Taking into account the effects of albedo, these show that the low energy cut-off to the electron power-law spectrum is typically ≲tens of keV, confirming that the accelerated electrons contain a large fraction of the energy released in flares. RHESSI has detected a high coronal hard X-ray source that is filled with accelerated electrons whose energy density is comparable to the magnetic-field energy density. This suggests an efficient conversion of energy, previously stored in the magnetic field, into the bulk acceleration of electrons. Anew, collisionless (Hall) magnetic reconnection process has been identified through theory and simulations, and directly observed in space and in the laboratory; it should occur in the solar corona as well, with a reconnection rate fast enough for the energy release in flares. The reconnection process could result in the formation of multiple elongated magnetic islands, that then collapse to bulk-accelerate the electrons, rapidly enough to produce the observed hard X-ray emissions. RHESSI's pioneering γ-ray line imaging of energetic ions, revealing footpoints straddling a flare loop arcade, has provided strong evidence that ion acceleration is also related to magnetic reconnection. Flare particle acceleration is shown to have a close relationship to impulsive Solar Energetic Particle (SEP) events observed in the interplanetary medium, and also to both fast coronal mass ejections and gradual SEP events. New instrumentation to provide the high sensitivity and wide dynamic range hard X-ray and γ-ray measurements, plus energetic neutral atom (ENA) imaging of SEPs above ∼2R⊙, will enable the next great leap forward in understanding particle acceleration and energy release is large solar eruptions—solar flares and associated fast coronal mass ejections (CMEs). Springer Science+Business Media B.V., 2011 Sun: flares nationallicence Sun: X-rays nationallicence Sun: acceleration nationallicence Sun: energetic particles nationallicence Space Science Reviews Springer Netherlands 159/1-4(2011-09-01), 421-445 0038-6308 159:1-4<421 2011 159 11214 https://doi.org/10.1007/s11214-011-9801-0 text/html Onlinezugriff via DOI 1 review-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11214-011-9801-0 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Lin R. Physics Department and Space Sciences Laboratory, UC Berkeley, 94720, Berkeley, CA, USA aut NATIONALLICENCE 773 0- Space Science Reviews Springer Netherlands 159/1-4(2011-09-01), 421-445 0038-6308 159:1-4<421 2011 159 11214 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer