000005693 001__ 5693
000005693 005__ 20220301165245.0
000005693 037__ $$aSCART-2022-0044
000005693 100__ $$aKahil, F.
000005693 245__ $$aThe Magnetic drivers of campfires seen by the Polarimetric and Helioseismic Imager (PHI) on Solar Orbiter
000005693 260__ $$c2022
000005693 520__ $$aThe Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter (SO) spacecraft observed small extreme ultraviolet (EUV) bursts, termed campfires, that have been proposed to be brightenings near the apexes of low-lying loops in the quiet-Sun atmosphere. The underlying magnetic processes driving these campfires are not understood. During the cruise phase of SO and at a distance of 0.523\,AU from the Sun, the Polarimetric and Helioseismic Imager on Solar Orbiter (SO/PHI) observed a quiet-Sun region jointly with SO/EUI, offering the possibility to investigate the surface magnetic field dynamics underlying campfires at a spatial resolution of about 380~km.  In 71\% of the 38 isolated events, campfires are confined between bipolar magnetic features, which seem to exhibit signatures of magnetic flux cancellation. The flux cancellation occurs either between the two main footpoints, or between one of the footpoints of the loop housing the campfire and a nearby opposite polarity patch. In one particularly clear-cut case, we detected the emergence of a small-scale magnetic loop in the internetwork followed soon afterwards by a campfire brightening adjacent to the location of the linear polarisation signal in the photosphere, that is to say near where the apex of the emerging loop lays. The rest of the events were observed over small scattered magnetic features, which could not be identified as magnetic footpoints of the campfire hosting loops. The majority of campfires could be driven by magnetic reconnection triggered at the footpoints, similar to the physical processes occurring in the burst-like EUV events discussed in the literature. About a quarter of all analysed campfires, however, are not associated to such magnetic activity in the photosphere, which implies that other heating mechanisms are energising these small-scale EUV brightenings.
000005693 594__ $$aSTCE
000005693 700__ $$aHirzberger, J.
000005693 700__ $$aSolanki, S.
000005693 700__ $$aManyAuthors, X.
000005693 700__ $$aBerghmans, D.
000005693 700__ $$aVerbeeck, C.
000005693 700__ $$aKraaikmap, E.
000005693 700__ $$aGissot, S.
000005693 773__ $$pAstronomy & Astrophysics$$y2022
000005693 8560_ $$fdavid.berghmans@observatoire.be
000005693 85642 $$ahttps://arxiv.org/abs/2202.13859
000005693 905__ $$aaccepted to be published in
000005693 980__ $$aREFERD