000005351 001__ 5351
000005351 005__ 20210528000521.0
000005351 0247_ $$2DOI$$a 10.1051/0004-6361/202038801
000005351 037__ $$aSCART-2021-0092
000005351 100__ $$aMorosan, D. E.; 
000005351 245__ $$aElectron acceleration and radio emission following the early interaction of two coronal mass ejections
000005351 260__ $$c2020
000005351 520__ $$aContext. Coronal mass ejections (CMEs) are large eruptions of magnetised plasma from the Sun that are often accompanied by solar radio bursts produced by accelerated electrons. Aims: A powerful source for accelerating electron beams are CME-driven shocks, however, there are other mechanisms capable of accelerating electrons during a CME eruption. So far, studies have relied on the traditional classification of solar radio bursts into five groups (Type I-V) based mainly on their shapes and characteristics in dynamic spectra. Here, we aim to determine the origin of moving radio bursts associated with a CME that do not fit into the present classification of the solar radio emission. Methods: By using radio imaging from the Nançay Radioheliograph, combined with observations from the Solar Dynamics Observatory, Solar and Heliospheric Observatory, and Solar Terrestrial Relations Observatory spacecraft, we investigate the moving radio bursts accompanying two subsequent CMEs on 22 May 2013. We use three-dimensional reconstructions of the two associated CME eruptions to show the possible origin of the observed radio emission. Results: We identified three moving radio bursts at unusually high altitudes in the corona that are located at the northern CME flank and move outwards synchronously with the CME. The radio bursts correspond to fine-structured emission in dynamic spectra with durations of ∼1 s, and they may show forward or reverse frequency drifts. Since the CME expands closely following an earlier CME, a low coronal CME-CME interaction is likely responsible for the observed radio emission. Conclusions: For the first time, we report the existence of new types of short duration bursts, which are signatures of electron beams accelerated at the CME flank. Two subsequent CMEs originating from the same region and propagating in similar directions provide a complex configuration of the ambient magnetic field and favourable conditions for the creation of collapsing magnetic traps. These traps are formed if a CME-driven wave, such as a shock wave, is likely to intersect surrounding magnetic field lines twice. Electrons will thus be further accelerated at the mirror points created at these intersections and eventually escape to produce bursts of plasma emission with forward and reverse drifts.
000005351 536__ $$aBRAIN.be project CCSOM/$$cBRAIN.be project CCSOM/$$fBRAIN.be project CCSOM
000005351 594__ $$aSTCE
000005351 700__ $$aPalmerio, E.; 
000005351 700__ $$aRasanen, J. E.; 
000005351 700__ $$aKilpua, E. K. J.; 
000005351 700__ $$aMagdalenic, J.; 
000005351 700__ $$aLynch, B. J.; 
000005351 700__ $$aKumari, A.; 
000005351 700__ $$aPomoell, J.; 
000005351 700__ $$aPalmroth, M.
000005351 773__ $$p Astronomy & Astrophysics$$v642$$y2020
000005351 8560_ $$fjasmina.magdalenic@observatoire.be
000005351 905__ $$apublished in
000005351 980__ $$aREFERD