Numerical simulations of tangential microwave launching for EC heating in a tokamak

Balakina, M. A.; Smolyakova, O. B.; Tokman, M. D.

doi:10.1134/1.1538502

Cited by 14 publications

(19 citation statements)

References 10 publications

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“…far from the cut-off, the finite derivatives of the weakly relativistic Hamiltonian do not produce any significant error. This result has been supported by the benchmark against the WR RTC code [49]. Furthermore, in most typical ECRH/ECCD scenarios for tokamaks and stellarators, where the kinetic effects in wave propagation are negligible, the "cold" Hamiltonian can be applied.…”

Section: Ray-tracing Equationsmentioning

confidence: 61%

Ray-tracing code TRAVIS for ECR heating, EC current drive and ECE diagnostic

Marushchenko

Turkin

Maaßberg

2014

Computer Physics Communications

109

108

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A description of the recently developed ray-tracing code TRAVIS is given together with the theoretical background, results of benchmarking and examples of application. The code is written for electron cyclotron studies with emphasis on heating, current drive and ECE diagnostic. The code works with an arbitrary 3D magnetic equilibrium being applicable for both stellarators and tokamaks. The equations for ray tracing are taken in the weakly relativistic approach, i.e. with thermal effects taken into account, while the absorption, current drive and emissivity are calculated in the fully relativistic approach. For the calculation of ECCD, an adjoint technique with parallel momentum conservation is applied. The code is controlled through a specially designed graphical user interface, which allows the preparation of the input parameters and viewing the results in convenient (2D and 3D) form.

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Section: Ray-tracing Equationsmentioning

confidence: 61%

Ray-tracing code TRAVIS for ECR heating, EC current drive and ECE diagnostic

Marushchenko

Turkin

Maaßberg

2014

Computer Physics Communications

109

108

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“…The TRAVIS code has been benchmarked against the old W7-AS code [10], the code WR RTC [19] and the code TORBEAM [20]. Additionally, the code was successfully tested on the ITER reference Scenario-2 [15] against several other predictions collected by R. Prater [6,7] (the results of this benchmark are not included in the cited papers).…”

Section: Description Of the Travis Codementioning

confidence: 99%

Electron cyclotron current drive calculated for ITER conditions using different models

2008

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Abstract. The current drive efficiency for the ITER reference Scenario-2 has been calculated by the newly developed ray-tracing code TRAVIS for both the upper and equatorial launcher. For comparison, two adjoint approach models are applied, the high-speed-limit model and a model with the parallel momentum conservation taken into account. It is shown, that in the angle range expected as optimal launch angles the momentum conservation correction produces a non-negligible contribution in ECCD, leading to the necessity to revise the previous predictions carefully. Additionally, the scenario with reduced magnetic field is checked. It is shown, that the ECCD efficiency (as well as the deposition profile) for the equatorial launcher may significantly be changed due to unwanted absorption at the higher (parasitic) harmonics.

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“…contours is fairly small [37,38] (small gradient of B along the rays) leading to high absorption, and the deposition is very sensitive to small changes of B, but also to the local electron temperatures due to the relativistic down-shift of the resonant cyclotron frequency (this effect is expected to be very important for the CERC scenarios at LHD with the very high T e , but low n e ). An "anomalous dispersion" effect [39], which can lead to the bending of the rays away from the resonance and is only obtained in the tracing with the weakly relativistic (hot) dispersion [40], is negligible for the low densities in LHD. Ray-tracing calculations [38,41] for the LHD inward-shifted configurations (with fairly high B-gradient along the rays, i.e.…”

Section: B Ech Operation Modes and Depositionmentioning

confidence: 99%

Common Features of Core Electron-Root Confinement in Helical Devices

Yokoyama

Maaßberg

Beidler

et al. 2006

Fusion Science and Technology

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The characteristics of core electron-root confinement (CERC) in helical devices are illustrated using results from the four different experiments, CHS, LHD, TJ-II and W7-AS. Common features include strongly peaked electron temperature profiles and large positive radial electric fields, E r , in the core region for discharges with sufficient central electron cyclotron heating (ECH). Such observations are consistent with a transition to the "electron-root" solution of the ambipolarity condition for E r , a feature of neoclassical theory which is unique to non-axisymmetric configurations. The magnetic topology of the configuration plays a role in this transition and thresholds are found for the particle density and ECH power, in accordance with neoclassical expectations. Neoclassical theory alone cannot explain all observations, however, as CERC formation can also be influenced by ECH-driven convective fluxes of localized electrons and by the presence of magnetic islands in the core region. This is the first report describing collaborative activities within the framework of the International Stellarator Profile Data Base.2

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Numerical simulations of tangential microwave launching for EC heating in a tokamak

Cited by 14 publications

References 10 publications

Ray-tracing code TRAVIS for ECR heating, EC current drive and ECE diagnostic

Ray-tracing code TRAVIS for ECR heating, EC current drive and ECE diagnostic

Electron cyclotron current drive calculated for ITER conditions using different models

Common Features of Core Electron-Root Confinement in Helical Devices

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