Seminar by Dr. Wenzhi Ruan (KU Leuven)
Title: MHD turbulence formation in the cusp region of solar flares
Abstract:
The turbulence in solar flares, which is implicated in the acceleration of high-energy electrons, remains a topic of scientific inquiry. In a recent study, we employed a 3D magnetohydrodynamic simulation that incorporates the magnetic reconnection process to successfully reproduce observed turbulence patterns. The turbulence arises from complex non-linear interactions between the outflows from the magnetic reconnection site and the magnetic arcades below it. Of particular importance is the Kelvin-Helmholtz instability (KHI), driven by shear flows, which plays a pivotal role in generating turbulent vortices. The resulting turbulence occurs above high-density flare loops and propagates along the magnetic field to the chromospheric footpoints as Alfvénic perturbations. Synthetic views and spectral analyses exhibit remarkable agreement with observational results obtained from extreme ultraviolet (EUV) observations and Hinode-EIS spectra. Energy analysis further reveals that more than 10% of the kinetic energy from the reconnection downflows can be converted into turbulent energy through KHI. These findings provide valuable insights into the formation of plasma turbulence during solar flares and its potential implications for the acceleration of high-energy particles.
Where: The seminar can be followed in person in building 200B, room 02.16 or online at the following link:
https://eu.bbcollab.com/guest/6fc7259fc2ba4f29af721ccb6a19eefd
