Analysis of the Tore Supra ICRF antenna with TOPICA

Milanesio, Daniele; Lancellotti, V.; Colas, L.; Maggiora, Riccardo; Kyrytsya, V.; Vecchi, G.

doi:10.1088/0741-3335/49/4/005

Cited by 21 publications

(21 citation statements)

References 19 publications

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“…3 [21]. This is in agreement with earlier TOPICA validation on Tore Supra [28], DIII-D [29] and Alcator-CMOD [27] and, provided the edge density profiles used are realistic, gives confidence in the predictive capability of the code for ITER. …”

Section: Validation Of Iter Coupling Predictionssupporting

confidence: 86%

The role of JET for the preparation of the ITER exploitation

Romanelli

Laxåbäck

Durodié³

et al. 2011

Fusion Engineering and Design

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Section: Validation Of Iter Coupling Predictionssupporting

confidence: 86%

The role of JET for the preparation of the ITER exploitation

Romanelli

Laxåbäck

Durodié³

et al. 2011

Fusion Engineering and Design

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“…Moreover, the electric field map have been computed by TOPICA code able to solve a 3D electric field in front of the ICRF antenna. 20 The plasma simulated is a deuterium plasma for simplification ͑obviously ITER plasma is a mixture of 50% of deuterium and 50% of tritium͒ and the parameters used Table I for each scenario. lx and ly are the radial width and the poloidal height of the simulated box.…”

Section: Rectified Potential Simulation Applied To Iter Icrf Antennamentioning

confidence: 99%

Broadening of rectified potential structures induced by rf currents in a magnetized plasma: Application to ITER scrape-off-layer

Faudot¹,

Colas

Heuraux³

et al. 2010

Physics of Plasmas

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International audienceMeasurements show that the vicinity of powered ion cyclotron range of frequency (ICRF) antennae is biased positively with respect to its environment [ J. Gunn et al., Proc. 22nd IAEA Fusion Energy Conference, Geneva 2008, EX/P6-32 ]. This is attributed to radio-frequency (rf) sheath rectification. The radial penetration of these direct current (dc) potentials from ICRF launchers into the tokamak scrape-off layer (SOL) determines the power deposition on the walls and especially on the antenna structure, which is a key point for long time clean discharges. Within independent flux tube models of rf sheath rectification the radial penetration of dc potentials is determined by the skin depth x0 = c/ωpe for the slow wave. When self-consistent exchange of transverse rf current is allowed between neighboring flux tubes, such a structure can be broadened radially up to a characteristic transverse length L. Broadening arises as soon as L>x0. A linear modeling of the process gives a first evaluation of the theoretical length L = (L∥ρci/2)1/2. Within the “flute assumption,” it scales with the length L∥ of open flux tubes and the ion Larmor radius Ωci. This trend has been confirmed by nonlinear fluid simulations using the SEM code taking into account nonlinearities of the sheath dynamics. Parametric regimes are outlined where broadening or nonlinearity arise. Langmuir probe measurements on Tore Supra suggest that the observed broadening is lower than predicted by the code. This suggests that actual rf current exchanges probably do not occur over the whole length of magnetic field lines but only on a fraction of it. This “effective parallel magnetic connection length” L∥eff is estimated from the measurements. The model is finally applied to several potential maps generated by an ITER antenna, with different plasma parameters depending on possible SOL scenarios in ITER, and “reasonable assumptions” about L∥eff. It comes out that L ranges between 1 and 10 cm depending on local L∥eff and on typical ITER plasma parameters

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“…• in the phase of Γ (in many cases better, see [1] for details); the JET and Tore Supra studies both report TOPICA results well within the measurement error bars (in the latter the coupling to the plasma has been evaluated by integrating the RF current over the strap length, see [3] for details). The DIII-D study reports very good absolute agreement, especially in H-mode [4].…”

Section: Introductionmentioning

confidence: 69%

A detailed comparison of antenna impedance measurements on ASDEX Upgrade with the ion cyclotron range of frequencies antenna code TOPICA

et al. 2015

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Abstract. New antenna diagnostics on ASDEX Upgrade, in the form of voltage and current probe pairs on the feeding lines of each ICRF antenna, close to the input ports, has made it possible to study in detail the behavior of the ASDEX Upgrade two-strap antenna under changing loading conditions, and compare these measurements with results of simulations using the TOPICA code. The present work extends previous studies by using the input impedance (more precisely, the complex voltage reflection coefficient Γ) on each antenna port for comparison, instead of the more commonly used loading resistance or coupled power. The electron density profiles used for the simulation were reconstructed from DCN interferometer and Lithium beam emission spectroscopy measurements, ELMsynchronized and averaged over time intervals from 10 to 200 ms depending on the case; 112 cases were compared from seven ASDEX Upgrade discharges with widely different plasma parameters and two operating frequencies (30 and 36.5 MHz). Very good agreement in |Γ| is found with the measurements on antenna 3 (< 3% averaged over a shot), good agreement is found with antennas 1 and 2 (< 10%); the code reproduces the correct trend in loading resistance R L in a significant majority of cases, although the discrepancies in the absolute values can be rather high (up to ∼ 50%) due to high reflection. Sources of discrepancy are discussed.PACS numbers: 52.50.Qt TOPICA study on ASDEX Upgrade 2

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Analysis of the Tore Supra ICRF antenna with TOPICA

Cited by 21 publications

References 19 publications

The role of JET for the preparation of the ITER exploitation

The role of JET for the preparation of the ITER exploitation

Broadening of rectified potential structures induced by rf currents in a magnetized plasma: Application to ITER scrape-off-layer

A detailed comparison of antenna impedance measurements on ASDEX Upgrade with the ion cyclotron range of frequencies antenna code TOPICA

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