Detailed measurements of the electron cyclotron current drive efficiency on DIII-D

Petty, C. C.; Prater, R.; Lohr, J.; Luce, T. C.; Fox, W.; Harvey, R. W.; Kinsey, J. E.; Lao, L. L.; Makowski, M. A.

doi:10.1088/0029-5515/42/12/303

Cited by 73 publications

(86 citation statements)

References 63 publications

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“…Still, unresolved questions with significance for ITER remain. Anomalous transport has been credited for the discrepancy between ray tracing predictions of ECCD profiles and experimentally measured profiles, which are spatially broader [5] [6]. Work at TCV on ECCD [7] casts doubt on anomalous transport as a primary driver of broadening.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Measurement of ECH Deposition Broadening: Beyond Anomalous Transport

et al. 2017

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Abstract. This work provides a first experimental measurement of broadened ECH deposition on the DIII-D tokamak. As seen in theory[1] and simulation [2], refraction by edge density fluctuations shifts the path of RF waves, altering ECH and ECCD deposition. This paper reports on an initial experimental confirmation of broadened ECH deposition on DIII-D tokamak. T e measurements from a 48 channel 2nd Harmonic ECE Radiometer digitized at 500 kHz are used with a set of broadened trial ECH deposition functions to calculate time-dependent, modulation-induced heat fluxes. The fitting of convective and diffusive transport to these fluxes allows different ECH deposition profiles to be compared. The best-fit ECH deposition produces reasonable transport coefficients which compare favorably with simulation. This method is applied to a set of L-and H-mode DIII-D discharges. Accounting for diffusive, convective, and coupled transport, the ECH deposition profile is found to be 2 to 3 times wider than predicted by TORAY-GA ray tracing.

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Section: Introductionmentioning

confidence: 99%

“…ECCD measurements can be made by Motional Stark Effect(MSE) [6]. MSE measures the change in pitch angle of magnetic field lines when ECCD is switched from co-to counter-current drive.…”

Section: Introductionmentioning

confidence: 99%

Experimental Measurement of ECH Deposition Broadening: Beyond Anomalous Transport

et al. 2017

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“…Extensive studies on DIII-D have shown that the experimentally measured EC driven current is in good agreement with predictions from combined ray-tracing and FokkerPlanck code calculations provided the synergy between the ECCD and a residual parallel electric field is properly accounted for [31]. Full non-inductive current drive over several current diffusion times has been demonstrated on TCV [32].…”

Section: Iiib Electron Cyclotron Current Drive (Eccd)mentioning

confidence: 54%

Non-Inductive Current Drive

Westerhof

2012

Fusion Science and Technology

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“…Accurate modelling requires a verified theory to allow computation of the ECCD. We have performed extensive theory-experiment comparisons over the past several years [51,52]. As is illustrated in figures 8 and 9, these investigations show excellent agreement between the measured ECCD and the predictions of quasilinear theory embodied in the CQL3D code [53].…”

Section: Current Density Profile Controlmentioning

confidence: 96%

Overview of recent experimental results from the DIII-D advanced tokamak program

Team

2003

Nucl. Fusion

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The DIII-D research program is developing the scientific basis for advanced tokamak (AT) modes of operation in order to enhance the attractiveness of the tokamak as an energy producing system. Since the last international atomic energy agency (IAEA) meeting, we have made significant progress in developing the building blocks needed for AT operation: (1) we have doubled the magnetohydrodynamic (MHD) stable tokamak operating space through rotational stabilization of the resistive wall mode; (2) using this rotational stabilization, we have achieved β N H 89 10 for 4τ E limited by the neoclassical tearing mode (NTM); (3) using real-time feedback of the electron cyclotron current drive (ECCD) location, we have stabilized the (m, n) = (3, 2) NTM and then increased β T by 60%; (4) we have produced ECCD stabilization of the (2, 1) NTM in initial experiments; (5) we have made the first integrated AT demonstration discharges with current profile control using ECCD; (6) ECCD and electron cyclotron heating (ECH) have been used to control the pressure profile in high performance plasmas; and (7) we have demonstrated stationary tokamak operation for 6.5 s (36τ E ) at the same fusion gain parameter of β N H 89 /q 2 95 ∼ = 0.4 as ITER but at much higher q 95 = 4.2. We have developed general improvements applicable to conventional and AT operating modes: (1) we have an existence proof of a mode of tokamak operation, quiescent H-mode, which has no pulsed, edge localized modes (ELM) heat load to the divertor and which can run for long periods of time (3.8 s or 25τ E ) with constant density and constant radiated power; (2) we have demonstrated real-time disruption detection and mitigation for vertical disruption events using high pressure gas jet injection of noble gases; (3) we have found that the heat and particle fluxes to the inner strike points of balanced, double-null divertors are much smaller than to the outer strike points. We have made detailed investigations of the edge pedestal and scrape-off layer (SOL): (1) atomic physics and plasma physics both play significant roles in setting the width of the edge density barrier in H-mode; (2) ELM heat flux conducted to the divertor decreases as density increases; (3) intermittent, bursty transport contributes to cross field particle transport in the SOL of H-mode and, especially, L-mode plasmas.

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Detailed measurements of the electron cyclotron current drive efficiency on DIII-D

Cited by 73 publications

References 63 publications

Experimental Measurement of ECH Deposition Broadening: Beyond Anomalous Transport

Experimental Measurement of ECH Deposition Broadening: Beyond Anomalous Transport

Non-Inductive Current Drive

Overview of recent experimental results from the DIII-D advanced tokamak program

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