Hall effects on scale-hierarchy in MHD turbulence etc15 Tracking Number 91Presentation: Session: Magnetohydrodynamics 1 Room: Room F Session start: 10:30 Tue 25 Aug 2015 Hideaki Miura miura.hideaki@nifs.ac.jp Affifliation: National Institute for Fusion Science Tomoharu Hatori hatori.tomoharu@nifs.ac.jp Affifliation: Graduate University of Advanced Studies Keisuke Araki araki@are.ous.ac.jp Affifliation: Okayama University of Science Topics: - MHD turbulence, - Vortex dynamics and structure formation Abstract: Direct numerical simulations of MHD turbulence with and without uniform magnetic field are carried out to study the Hall effects on scale-hierarchy in MHD turbulence. It is observed that vortex and current sheets are filamented either by the Kelvin-Helmholtz instability or magnetic reconnection in case of Hall MHD turbulence, while the filamentation is not observed without the Hall term. We show that the filamentation occurs not only for scales smaller than the ion skin depth, which is indicated by the Hall parameter, but also for scales larger than the ion skin depth, affecting turbulence statistics. It is also shown that the Hall effects can be modelled by a Smagorinsky-type model effectively for high wave number regions. |