Generating system for Alfvén waves in TCA/BR

Ruchko, L.; Galvão, R. M. O.; Nascimento, I. C.; Ozono, Edson Moriyoshi; Degasperi, Francisco Tadeu; Lerche, E.

doi:10.1016/b978-0-444-82762-3.50115-4

Cited by 4 publications

(11 citation statements)

References 8 publications

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“…21 However, the simulations can be carried out assuming a circular crosssection tokamak geometry with the following parameters: minor radius aϭ0.18 m; major radius R 0 ϭ0.61 m; antenna surface radius bϭ0.184 m; wall radius dϭ0.23 m. In its initial phase, the machine will be operated with a maximum toroidal magnetic field B t ϭ1T and a maximum plasma current I p ϭ120 kA, in a hydrogen plasma. The calculations are carried out assuming a temperature profile given by T ␣ ϭT ␣0 (1Ϫr 2 /a 2 ) 2 , with ␣ϭe,i, T e0 ϭ500 and T i0 ϭ300 eV, respectively.…”

Section: Alfvé N Wave Dissipationmentioning

confidence: 99%

“…The real structure of the new TCABR antenna system is taken into account through coefficients calculated in Ref. 21. We consider only one antenna mode that corresponds to the main component given by the Fourier analysis of the actual antenna system.…”

Section: Alfvé N Wave Dissipationmentioning

confidence: 99%

“…13 The real structure of the new TCABR antenna system is considered via coefficients calculated in Ref. 21. For comparison, some calculations are reproduced with a locally developed kinetic cylindrical code.…”

Section: Introductionmentioning

confidence: 99%

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Calculations of wave excitation and dissipation in Tokamak Chauffage Alfvén wave heating experiment in Brazil

et al. 1999

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The results of numerical calculations of Alfvén wave absorption are discussed for the experimental conditions foreseen for the Tokamak Chauffage Alfvén wave heating experiment in Brazil (TCABR) [Nucl. Fusion 30, 503 (1996)]. In particular, the effect of toroidal mode coupling on the power deposition of Global Alfvén Wave (GAW) eigenmodes is carefully investigated. Resonant absorption of the toroidally coupled sidebands causes a broad power deposition close to the plasma boundary which can surpass the power deposition of the main GAW at the plasma center. However, the wave absorption can be somewhat optimized by a proper choice of mode spectrum. The excitation of a pure mode spectrum centered at the toroidal mode numbers n=−4 and −6 leads to better plasma coupling than a spectrum centered at n=−2. Finally, it is shown that a small population of light impurities in a hydrogen plasma can strongly modify the dispersion of the GAW and the toroidal Alfvén continuum.

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Section: Alfvé N Wave Dissipationmentioning

confidence: 99%

Section: Alfvé N Wave Dissipationmentioning

confidence: 99%

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Calculations of wave excitation and dissipation in Tokamak Chauffage Alfvén wave heating experiment in Brazil

et al. 1999

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“…The plasma condition before perturbation is typical of that obtained for Ohmically heated tokamaks. Another condition is obtained by externally injecting Alfvén waves into the plasma using a rf antenna for plasma heating and non-inductive current drive [12,13]. In our experiment, we use a particular arrangement of these facilities to investigate the scrape-off layer turbulence modifications introduced by the rf injection.…”

Section: Introductionmentioning

confidence: 99%

Turbulence and transport in the scrape-off layer TCABR tokamak

Ferreira¹,

Heller²,

Caldas³

et al. 2004

Plasma Phys. Control. Fusion

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We study the scrape-off layer turbulence and transport in Tokamak Chauffage Alfvén Brésilien (TCABR) before and during the launching of radio frequency excited waves that interact with the boundary plasma. We present the main characteristics of the background electrostatic fluctuations and the intermittent bursts. During the perturbation, the plasma turbulence intensity increases and the average phase velocity reverses its direction. The total turbulence driven transport and the transport radially convected by the intermittent fluctuation bursts also increase with the perturbation. The probability distributions of the bursts have long tails, resembling those typical of flight distributions with a decay parameter increasing with the wave excitation.

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“…A complete new antenna was designed and installed in the device [25], and some results (with and without Faraday screen) of AW heating and current drive (without any profile measurements) were reported [26,27,28]. Therefore, it is mandatory to investigate theoretically and experimentally the AW power deposition and RF field profiles for the plasma parameters of TCABR with the new antenna.…”

Section: Introductionmentioning

confidence: 99%

Results of localized Alfvén wave heating in TCABR

Elfimov¹,

Lerche²,

Galvão³

et al. 2004

Braz. J. Phys.

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Using two dimensional numerical codes, we show that the direct electron heating found with electron cyclotron emission (ECE) radiometry is related to local Alfvén wave resonances in Tokamak Chauffage Alfvén Brésilean (TCABR) plasmas. The m/N =1/2, 0/2 and 0/3 modes are dominant in the observed wave heating, due to Alfvén wave continuum absorption. In particular, the resonant absorption of the m = 0 sideband harmonic plays an important role in the central core and peripheral heating. The increase of the electron temperature during the radio frequency pulse was accompanied by a local density rise that produced a cut-off of the ECE emission. The observed heating profile is also consistent with the reflectometer measurements of the density fluctuations induced by radio frequency fields in the local Alfvén wave resonance of the m/N =-1/-2, 1/-3 modes in TCABR.

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Generating system for Alfvén waves in TCA/BR

Cited by 4 publications

References 8 publications

Calculations of wave excitation and dissipation in Tokamak Chauffage Alfvén wave heating experiment in Brazil

Calculations of wave excitation and dissipation in Tokamak Chauffage Alfvén wave heating experiment in Brazil

Turbulence and transport in the scrape-off layer TCABR tokamak

Results of localized Alfvén wave heating in TCABR

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