000005334 001__ 5334
000005334 005__ 20210502163914.0
000005334 0247_ $$2DOI$$a10.1051/0004-6361/202140638
000005334 037__ $$aSCART-2021-0081
000005334 100__ $$aChen, Y.
000005334 245__ $$aTransient small-scale brightenings in the quiet solar corona: A model for campfires observed with Solar Orbiter
000005334 260__ $$c2021
000005334 520__ $$aContext. Recent observations by the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter have characterized prevalent small- scale transient brightenings in the corona above the quiet Sun termed campfires. Aims. In this study we search for comparable brightenings in a numerical model and then investigate their relation to the magnetic field and the processes that drive these events. Methods. We used the MURaM code to solve the 3D radiation magnetohydrodynamic equations in a box that stretches from the upper convection zone to the corona. The model self-consistently produces a supergranular network of the magnetic field and a hot corona above this quiet Sun. For the comparison with the model, we synthesized the coronal emission as seen by EUI in its 174 Å channel, isolated the seven strongest transient brightenings, and investigated the changes of the magnetic field in and around these in detail. Results. The transients we isolated have a lifetime of about 2 minutes and are elongated loop-like features with lengths around 1 Mm to 4 Mm. They tend to occur at heights of about 2 Mm to 5 Mm above the photosphere, a bit offset from magnetic concentrations that mark the bright chromospheric network, and they reach temperatures of above 1 MK. As a result, they very much resemble the larger campfires found in observations. In our model most events are energized by component reconnection between bundles of field lines that interact at coronal heights. In one case, we find that untwisting a highly twisted flux rope initiates the heating. Conclusions. Based on our study, we propose that the majority of campfire events found by EUI are driven by component reconnection and our model suggests that this process significantly contributes to the heating of the corona above the quiet Sun.
000005334 594__ $$aSTCE
000005334 6531_ $$aSun: magnetic fields
000005334 6531_ $$aSun: corona
000005334 6531_ $$aMagnetohydrodynamics(MHD)
000005334 700__ $$aPrzybylski, D.
000005334 700__ $$aPeter, H.
000005334 700__ $$aTian, H.
000005334 700__ $$aAuchère, F.
000005334 700__ $$aBerghmans, D.
000005334 773__ $$nSpecial Issue "Solar Orbiter First Results"$$pAstronomy and Astrophysics$$y2021
000005334 8560_ $$fdavid.berghmans@observatoire.be
000005334 85642 $$ahttps://www.aanda.org/component/article?access=doi&doi=10.1051/0004-6361/202140638
000005334 85642 $$ahttps://www.aanda.org/articles/aa/pdf/forth/aa40638-21.pdf
000005334 905__ $$aaccepted to be published in
000005334 980__ $$aREFERD