Göttingen 2025 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 11: Sun and Heliosphere IV
EP 11.3: Talk
Thursday, April 3, 2025, 14:15–14:30, ZHG101
Quasi-separatrix-layers channel solar wind outflows in coronal hole — •Kamlesh Bora, Pradeep Chitta, Yajie Chen, and Damien Przybylski — Max-Planck Institute for Solar System Research, 37077 Göttingen, Germany
Observations indicate that small-scale, transient jetlets at the base of plumes and upflows within coronal holes contribute substantially to the mass and energy flux of the solar wind. We use three-dimensional radiation magnetohydrodynamic (MHD) simulations of a coronal hole plume, conducted with the MURaM code, to examine the magnetic origins and driving mechanisms of these upflows/jets in the solar atmosphere. Our simulations show that interactions between the magnetic field of the plume with the surrounding like-polarity magnetic patches creates a strong quasi-separatrix layer (QSL), characterised by a filamentary fine structure. We analyse the resulting plasma flows and temperature structure, comparing them with synthesised 174 Å Extreme Ultraviolet Imager (EUI) emission at this QSL. We noted a transition from cooler downflows in the lower atmosphere to persistent hotter upflows in the corona at the QSL, with a substantial mass flux of 10−8 g cm−2 s−1, that could in principle be channelled as the solar wind outflow. Our simulations go beyond the traditional picture of upflows originating from an interchange reconnection between open and closed field lines, and show the important role of QSLs in the formation of the solar wind.
Keywords: Coronal hole; Plume; Solar wind; Magnetohydrodynamics (MHD) simulations; Reconnection