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Multiscale structures and noise in magnetized plasmas line-tied at conducting surfaces

Published online by Cambridge University Press:  28 March 2019

A. B. Hassam  and
Yi-Min Huang
A. B. Hassam*
Affiliation:
Department of Physics, University of Maryland, College Park, Maryland, 20742, USA
Yi-Min Huang
Affiliation:
Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey, 08544, USA
*
†Email address for correspondence: hassam@umd.edu
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Abstract

In magnetized plasma situations where magnetic fields intersect massive conducting boundaries, ‘line-tied’ boundary conditions are often used, analytically and in numerical simulations. For ideal magnetohydrodynamic (MHD) plasmas, these conditions are arrived at given the relatively long time scales for magnetic fields penetrating resistively into good conductors. Under line-tied boundary conditions, numerical simulations often exhibit what could be construed as numerical ‘noise’ emanating from the boundaries. We show here that this ‘noise’ is real. By combining numerical and analytical methods, we highlight the existence of sharp spatial structures near the conductors and confirm the appearance of short wavelength structures riding on long wavelength modes. We conclude that, for numerical fidelity, the short multiscale structures need to be resolved. Generally, the short structure widths scale as the square root of the plasma $\unicode[STIX]{x1D6FD}$.

Keywords

astrophysical plasmasfusion plasmaplasma simulation
Type
Research Article
Information
Journal of Plasma Physics , Volume 85 , Issue 2 , April 2019 , 905850206
Copyright
© Cambridge University Press 2019 

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