Testing gyrokinetic simulations of electron turbulence

Journal Article · Fri Jun 01 04:00:00 EDT 2012 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/52/6/063028· OSTI ID:1564877

Holland, C.; DeBoo, J. C.; Rhodes, T. L.; Schmitz, L.; Hillesheim, J. C.; Wang, G.; White, A. E.; Austin, M. E.; Doyle, E. J.; Peebles, W. A.; Petty, C. C.; Zeng, L.; Candy, J.

An extensive set of tests comparing gyrokinetic predictions of temperature-gradient driven electron turbulence to power balance transport analyses and fluctuation measurements are presented. These tests use data from an L-mode validation study on the DIII-D tokamak (Luxon 2002 Nucl. Fusion 42 614) in which the local value of $$a/L_{T_{\rm e} } =-(a/T_{\rm e} )({\rm d}T_{\rm e} /{\rm d}r)$$ is varied by modulated electron cyclotron heating; the GYRO code (Candy and Waltz 2003 J. Comput. Phys. 186 545) is used to make the gyrokinetic predictions. Using a variety of novel measures, both local and global nonlinear simulations are shown to predict key characteristics of the electron energy flux Qe and long-wavelength (low-k) Te fluctuations, but systematically underpredict (by roughly a factor of two) the ion energy flux Qi. A new synthetic diagnostic for comparison to intermediate wavelength Doppler backscattering measurements is presented, and used to compare simulation predictions against experiment. In contrast to the agreement observed in the low-k Te fluctuation comparisons, little agreement is found between the predicted and measured intermediate-k density fluctuation responses. The results presented in this paper significantly expand upon those previously reported in DeBoo et al (2010 Phys. Plasmas 17 056105), comparing transport and multiple turbulence predictions from numerically converged local and global simulations for all four experimental heating configurations (instead of only fluxes and low-k Te fluctuations for one condition) to measurements and power balance analyses.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Univ. of Texas, Austin, TX (United States); UT-Battelle LLC/ORNL, Oak Ridge, TN (Unted States); General Atomics, San Diego, CA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Univ. of California, San Diego, CA (United States); Univ. of California, Los Angeles, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: FG05-88ER53266; AC05-00OR22725; FC02-04ER54698; FC02-93ER54186; FG02-07ER54917; FG02-08ER54984; FG02-95ER54309; FG03-97ER54415
• OSTI ID: 1564877
• Journal Information: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 6 Vol. 52; ISSN 0029-5515
• Publisher: IOP Science
• Country of Publication: United States
• Language: English

Related Subjects

Physics