caa a22 4500 445346736 CHVBK 20180317142831.0 cr unu---uuuuu 170323e20110401xx s 000 0 eng 10.1007/s11207-011-9710-0 doi (NATIONALLICENCE)springer-10.1007/s11207-011-9710-0 Particle Acceleration and Propagation in Strong Flares without Major Solar Energetic Particle Events [Elektronische Daten] [K.-L. Klein, G. Trottet, S. Samwel, O. Malandraki] Solar energetic particles (SEPs) detected in space are statistically associated with flares and coronal mass ejections (CMEs). But it is not clear how these processes actually contribute to the acceleration and transport of the particles. The present work addresses the question why flares accompanied by intense soft X-ray bursts may not produce SEPs detected by observations with the GOES spacecraft. We consider all X-class X-ray bursts between 1996 and 2006 from the western solar hemisphere. 21 out of 69 have no signature in GOES proton intensities above 10MeV, despite being significant accelerators of electrons, as shown by their radio emission at cm wavelengths. The majority (11/20) has no type III radio bursts from electron beams escaping towards interplanetary space during the impulsive flare phase. Together with other radio properties, this indicates that the electrons accelerated during the impulsive flare phase remain confined in the low corona. This occurs in flares with and without a CME. Although GOES saw no protons above 10MeV at geosynchronous orbit, energetic particles were detected in some (4/11) confined events at Lagrangian point L1 aboard ACE or SoHO. These events have, besides the confined microwave emission, dm-m wave typeII and typeIV bursts indicating an independent accelerator in the corona. Three of them are accompanied by CMEs. We conclude that the principal reason why major solar flares in the western hemisphere are not associated with SEPs is the confinement of particles accelerated in the impulsive phase. A coronal shock wave or the restructuring of the magnetically stressed corona, indicated by the typeII and IV bursts, can explain the detection of SEPs when flare-accelerated particles do not reach open magnetic field lines. But the mere presence of these radio signatures, especially of a metric type II burst, is not a sufficient condition for a major SEP event. Springer Science+Business Media B.V., 2011 Corona, radio emission nationallicence Energetic particles, acceleration nationallicence Energetic particles, propagation nationallicence Flares, energetic particles nationallicence Flares, relation to magnetic field nationallicence Klein K.-L Observatoire de Paris, LESIA-CNRS UMR 8109, Univ. P & M Curie and Paris-Diderot, Observatoire de Meudon, 92195, Meudon, France aut Trottet G. Observatoire de Paris, LESIA-CNRS UMR 8109, Univ. P & M Curie and Paris-Diderot, Observatoire de Meudon, 92195, Meudon, France aut Samwel S. National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Cairo, Egypt aut Malandraki O. Institute of Astronomy and Astrophysics, National Observatory of Athens, 11810, Athens, Greece aut Solar Physics Springer Netherlands 269/2(2011-04-01), 309-333 0038-0938 269:2<309 2011 269 11207 https://doi.org/10.1007/s11207-011-9710-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-011-9710-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Klein K.-L Observatoire de Paris, LESIA-CNRS UMR 8109, Univ. P & M Curie and Paris-Diderot, Observatoire de Meudon, 92195, Meudon, France aut NATIONALLICENCE 700 1- Trottet G. Observatoire de Paris, LESIA-CNRS UMR 8109, Univ. P & M Curie and Paris-Diderot, Observatoire de Meudon, 92195, Meudon, France aut NATIONALLICENCE 700 1- Samwel S. National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Cairo, Egypt aut NATIONALLICENCE 700 1- Malandraki O. Institute of Astronomy and Astrophysics, National Observatory of Athens, 11810, Athens, Greece aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 269/2(2011-04-01), 309-333 0038-0938 269:2<309 2011 269 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer