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Title: Microturbulence study of the isotope effect

Abstract

The influence of the ion mass on the dynamics of magnetized plasmas is an important challenge in fusion research. The discrepancies between the improvement of the magnetic confinement with the ion mass in tokamak experiments and diffusive turbulent transport predictions have remained unexplained for several decades. We refer to this phenomenon as the isotope effect. In this paper, we study this effect with gyrokinetic theory using the GENE code. We find several sets of plasma parameters that correspond to low wavenumber turbulence for which the isotope effect is present, although the intensity is smaller than the experimental observations. We also relate these results to the zonal flow intensity of the system, which is characterized by the average shear flow rate.

Authors:
; ;  [1];  [1];  [2];  [3]
  1. Max-Planck-Institut für Plasmaphysik, Boltzmannstrasse 2, 85748 Garching (Germany)
  2. (United States)
  3. Laboratorio Nacional de Fusion, CIEMAT, 28040 Madrid (Spain)
Publication Date:
OSTI Identifier:
22407991
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 1; Other Information: (c) 2015 EURATOM; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; DYNAMICS; EXPERIMENTAL DATA; FLOW RATE; MAGNETIC CONFINEMENT; MASS; PLASMA; SHEAR; TOKAMAK DEVICES; TRANSPORT; TURBULENCE

Citation Formats

Bustos, A., Bañón Navarro, A., Görler, T., Jenko, F., Max-Planck/Princeton Center for Plasma Physics, Department of Physics and Astronomy, University of California, Los Angeles, California 90095, and Hidalgo, C. Microturbulence study of the isotope effect. United States: N. p., 2015. Web. doi:10.1063/1.4905637.
Bustos, A., Bañón Navarro, A., Görler, T., Jenko, F., Max-Planck/Princeton Center for Plasma Physics, Department of Physics and Astronomy, University of California, Los Angeles, California 90095, & Hidalgo, C. Microturbulence study of the isotope effect. United States. doi:10.1063/1.4905637.
Bustos, A., Bañón Navarro, A., Görler, T., Jenko, F., Max-Planck/Princeton Center for Plasma Physics, Department of Physics and Astronomy, University of California, Los Angeles, California 90095, and Hidalgo, C. Thu . "Microturbulence study of the isotope effect". United States. doi:10.1063/1.4905637.
@article{osti_22407991,
title = {Microturbulence study of the isotope effect},
author = {Bustos, A. and Bañón Navarro, A. and Görler, T. and Jenko, F. and Max-Planck/Princeton Center for Plasma Physics, Department of Physics and Astronomy, University of California, Los Angeles, California 90095 and Hidalgo, C.},
abstractNote = {The influence of the ion mass on the dynamics of magnetized plasmas is an important challenge in fusion research. The discrepancies between the improvement of the magnetic confinement with the ion mass in tokamak experiments and diffusive turbulent transport predictions have remained unexplained for several decades. We refer to this phenomenon as the isotope effect. In this paper, we study this effect with gyrokinetic theory using the GENE code. We find several sets of plasma parameters that correspond to low wavenumber turbulence for which the isotope effect is present, although the intensity is smaller than the experimental observations. We also relate these results to the zonal flow intensity of the system, which is characterized by the average shear flow rate.},
doi = {10.1063/1.4905637},
journal = {Physics of Plasmas},
number = 1,
volume = 22,
place = {United States},
year = {Thu Jan 15 00:00:00 EST 2015},
month = {Thu Jan 15 00:00:00 EST 2015}
}
  • Upon treatment with the solvent conjugate base, the primary reaction of substituted 1-phenylethyl chlorides is elimination to substituted styrenes in tert-butanol (t-BuOH)-10% v/v dimethyl sulfoxide (Me/sub 2/SO) at 60/sup 0/C and in bis(2-hydroxyethyl) ether-10% v/v Me/sub 2/SO at 45/sup 0/C. Kinetic studies using eight substituted chlorides show that these reactions are strongly accelerated by both electron-donating and electron-withdrawing substituents, probably indicating a fairly reactant-like E2 transition state with the mechanism changing from El-like E2 to ElcB-like E2 as the substituents change from electron donating group (EDG) to electron withdrawing (EWG). In this first carbon isotope effect study of an eliminationmore » reaction of an alkyl chloride, carbon-14 kinetic isotope effects have been measured in the alkoxide/bis(2-hydroxyethyl) ether-Me/sub 2/SO system for 1-(4-methylphenyl)ethyl-2-/sup 14/C chloride, k/sup ..beta../k = 1.038, 1-phenylethyl-2-/sup 14/C chloride, k/sup ..beta../k = 1.058, and 1-(4-chlorophenyl)ethyl-2-/sup 14/C chloride, k/sup ..beta../k = 1.068. Clearly none of these compounds reacts by an irreversible El mechanism, for which no ..beta..-carbon isotope effect should be observed. The trend in the results is what would be expected from increased C/sub ..beta../-H bond rupture as the E2 transition state shifts from El-like to ElcB-like. Theoretical calculations involving El-like E2 transition-state models show that in this region only for a reaction coordinate motion tht strongly couples C/sub ..beta../-H bond rupture, C/sub ..cap alpha../-C/sub ..beta../ double bond formation, and C/sub ..cap alpha../-Cl bond rupture does the calculated value for k/sup ..beta../k come into the experimentally observed range, and then only for reactant-like models. 2 figures, 5 tables.« less
  • The effect of zonal flow shear on the double tearing mode is investigated by solving the linear reduced two-fluid equations for the equilibrium including zonal flow. The zonal flow caused by microturbulence is obtained from nonlinear simulation results presented by A. Ishizawa and N. Nakajima [Phys. Plasmas 14, 040702 (2007)]. There is no clear evidence that could indicate whether the double tearing mode is stabilized or destabilized by the zonal flow.