000005011 001__ 5011
000005011 005__ 20201204135547.0
000005011 0247_ $$2DOI$$a10.1051/0004-6361/202038699 
000005011 037__ $$aSCART-2020-0182
000005011 100__ $$aKoukras, Alexandros
000005011 245__ $$aAnalyzing the propagation of EUV waves and their connection with type II radio bursts by combining numerical simulations and multi-instrument observations
000005011 260__ $$c2020
000005011 520__ $$aContext. EUV (EIT) waves are wavelike disturbances of enhanced extreme ultraviolet (EUV) emission that propagate away from an eruptive active region across the solar disk. Recent years have seen much debate over their nature, with three main interpretations: the fast-mode magneto-hydrodynamic (MHD) wave, the apparent wave (reconfiguration of the magnetic field), and the hybrid wave (combination of the previous two). Aims. By studying the kinematics of EUV waves and their connection with type II radio bursts, we aim to examine the capability of the fast-mode interpretation to explain the observations, and to constrain the source locations of the type II radio burst emission. Methods. We propagate a fast-mode MHD wave numerically using a ray-tracing method and the WKB (Wentzel-Kramers-Brillouin) approximation. The wave is propagated in a static corona output by a global 3D MHD Coronal Model, which provides density, temperature, and Alfvén speed in the undisturbed coronal medium (before the eruption). We then compare the propagation of the computed wave front with the observed wave in EUV images (PROBA2/SWAP, SDO/AIA). Lastly, we use the frequency drift of the type II radio bursts to track the propagating shock wave, compare it with the simulated wave front at the same instant, and identify the wave vectors that best match the plasma density deduced from the radio emission. We apply this methodology for two EUV waves observed during SOL2017-04-03T14:20:00 and SOL2017-09-12T07:25:00. Results. The simulated wave front displays a good qualitative match with the observations for both events. Type II radio burst emission sources are tracked on the wave front all along its propagation. The wave vectors at the ray-path points that are characterized as sources of the type II radio burst emission are quasi-perpendicular to the magnetic field. Conclusions. We show that a simple ray-tracing model of the EUV wave is able to reproduce the observations and to provide insight into the physics of such waves. We provide supporting evidence that they are likely fast-mode MHD waves. We also narrow down the source region of the radio burst emission and show that different parts of the wave front are responsible for the type II radio burst emission at different times of the eruptive event.
000005011 594__ $$aSTCE
000005011 6531_ $$amagnetohydrodynamics
000005011 6531_ $$atype II radio bursts
000005011 6531_ $$aEUV (EIT) waves
000005011 6531_ $$acorona
000005011 700__ $$aMarqué, Christophe
000005011 700__ $$aDowns, Cooper  
000005011 700__ $$aDolla, Laurent
000005011 773__ $$pAstronomy & Astrophysics$$v644$$y2020
000005011 8560_ $$falexandros.koukras@observatoire.be
000005011 905__ $$apublished in
000005011 980__ $$aREFERD