Bulletin of the American Physical Society
60th Annual Meeting of the APS Division of Plasma Physics
Volume 63, Number 11
Monday–Friday, November 5–9, 2018; Portland, Oregon
Session TP11: Poster Session VII: Basic Plasma Physics: Pure Electron Plasma, Strongly Coupled Plasmas, Self-Organization, Elementary Processes, Dusty Plasmas, Sheaths, Shocks, and Sources; Mini-conference on Nonlinear Waves and Processes in Space Plasmas - Posters; MHD and Stability, Transients (2), Runaway Electrons; NSTX-U; Spherical Tokamaks; Analytical and Computational Techniques; Diagnostics (9:30am-12:30pm)
Thursday, November 8, 2018
OCC
Room: Exhibit Hall A1&A
Abstract ID: BAPS.2018.DPP.TP11.79
Abstract: TP11.00079 : Dependence of Perpendicular Viscosity on Magnetic Fluctuations in a Stochastic Magnetic Field*
Presenter:
B.E. Chapman
(UW-Madison)
Authors:
B.E. Chapman
(UW-Madison)
R. Fridstrom
(KTH Royal Institute of Technology)
A.F. Almagri
(UW-Madison)
L. Frassinetti
(KTH Royal Institute of Technology)
P.R. Brunsell
(KTH Royal Institute of Technology)
T. Nishizawa
(UW-Madison)
J.S. Sarff
(UW-Madison)
In a magnetically confined plasma with a stochastic magnetic field, the dependence of the perpendicular viscosity on magnetic fluctuation amplitude has been measured for the first time [PRL 120, 225002 (2018)]. With a controlled, ∼ 10-fold variation in the fluctuation amplitude, the viscosity increases ∼100-fold, exhibiting the same (b/B)^2 dependence as the predicted rate of stochastic field line diffusion. The absolute value of the viscosity is well predicted by a model [Finn et al., 1992] based on momentum transport in a stochastic field, the first in-depth test of this model. Derived for the tokamak, we tested this model in MST RFP plasmas. The viscosity in MST plasmas reaches about 55 m^2/s and can exceed the Braginskii prediction by several-hundred-fold. Measurements of the viscosity in a stochastic topology are rare but can be of critical importance. Viscosity is a key parameter in visco-resistive nonlinear MHD modeling, which is being applied to stochastic scenarios like tokamak disruptions. Viscosity, like the resistivity, is likely to increase substantially during a disruption. And while the modeled resistivity, or at least the electron temperature, is sometimes based on experimental data, the viscosity is often assumed.
*Work supported by USDOE.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.DPP.TP11.79
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700