Progress and First Results With the New Multifrequency ECRH System for ASDEX Upgrade

Wágner, D.; Stöber, J.; Leuterer, F.; Sips, G.; Grunwald, Gerhard; Monaco, F.; Münich, M.; Poli, E.; Schütz, H.; Volpe, F.; Treutterer, W.; Zohm, H.; Franke, Thomas; Thumm, M.; Heidinger, R.; Gantenbein, G.; Meier, Andreas; Kasparek, W.; Lechte, C.; Litvak, A. G.; Денисов, Г. Г.; Чирков, А. В.; Tai, E.M.; Popov, L. G.; Nichiporenko, V. O.; Myasnikov, V.E.; Solyanova, E.A.; Malygin, S. A.

doi:10.1109/tps.2008.2011798

Cited by 16 publications

(15 citation statements)

References 14 publications

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“…On AUG the probing radiation is delivered by a dual frequency gyrotron normally used for electron cyclotron resonance heating (ECRH) at 140 GHz. The probing gyrotron is part of the ECRH-2 system on AUG [44][45][46] , which is comprised of four gyrotrons referred to here as gyrotrons 5-8 (gyrotrons 1-4 comprise the ECRH-1 system on AUG). The gyrotrons have separate transmission lines and launching antennae, which are mounted in close proximity above and below the equatorial midplane on the low-field side on the tokamak as illustrated in Fig.…”

Section: Overview Of Cts Systems On Asdex Upgradementioning

confidence: 99%

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

Stejner

Nielsen

Jacobsen

et al. 2014

Review of Scientific Instruments

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Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity and plasma composition.

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Section: Overview Of Cts Systems On Asdex Upgradementioning

confidence: 99%

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

Stejner

Nielsen

Jacobsen

et al. 2014

Review of Scientific Instruments

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“…A launcher that would span the whole parameter range listed in Table 2 is certainly unrealistic. Multi-frequency systems are rather challenging-even though such systems are actively being studied [48]. For these reasons we focus more on single-frequency systems.…”

Section: Ebw System Parametersmentioning

confidence: 99%

A survey of electron Bernstein wave heating and current drive potential for spherical tokamaks

et al. 2011

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The electron Bernstein wave (EBW) is typically the only wave in the electron cyclotron (EC) range that can be applied in spherical tokamaks for heating and current drive (H&CD). Spherical tokamaks (STs) operate generally in high-β regimes, in which the usual EC O-and X-modes are cut-off. In this case, EBWs seem to be the only option that can provide features similar to the EC waves-controllable localized H&CD that can be utilized for core plasma heating as well as for accurate plasma stabilization.The EBW is a quasi-electrostatic wave that can be excited by mode conversion from a suitably launched O-or X-mode; its propagation further inside the plasma is strongly influenced by the plasma parameters. These rather awkward properties make its application somewhat more difficult. In this paper we perform an extensive numerical study of EBW H&CD performance in four typical ST plasmas (NSTX L-and H-mode, MAST Upgrade, NHTX). Coupled ray-tracing (AMR) and Fokker-Planck (LUKE) codes are employed to simulate EBWs of varying frequencies and launch conditions, which are the fundamental EBW parameters that can be chosen and controlled. Our results indicate that an efficient and universal EBW H&CD system is indeed viable. In particular, power can be deposited and current reasonably efficiently driven across the whole plasma radius. Such a system could be controlled by a suitably chosen launching antenna vertical position and would also be sufficiently robust.

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“…A large body of work has been done to discuss the trajectory and deposition of ordinary modes and extraordinary modes on tokamaks based on the dispersion relationship in Maxwellian plasma [3∼5] carried out in the 1980s. With the development of a high-frequency gyrotron, in recent years a second harmonic extraordinary wave (X2-mode, "X" is short for extraordinary and "2" is short for second harmonic) has been applied to the ECRH and electron cyclotron current drive on such tokamaks as ASDEX Upgrade [6] , DIII-D [7] and TCV [8] etc., as it has a better accessibility than the fundamental ordinary wave (O1-mode, "O" is short for ordinary and "1" is short for first harmonic). The physics model of ECRH is well validated in previous experiments and theoretical works.…”

Section: Introductionmentioning

confidence: 99%

Electron Cyclotron Harmonic Wave Heating in Tokamak Plasmas with Different Polarization Modes

Min¹,

Chen²,

Tang

2013

Plasma Sci. Technol.

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Electron cyclotron heating on HL-2A has been simulated by TORAY-GA with a second harmonic extraordinary wave and a fundamental ordinary wave. The results show that the wave absorption of the second harmonic extraordinary wave is better than that of the fundamental ordinary wave. In order to understand the interaction mechanism between electrons and the two different polarization modes, the energy exchange between electrons and the two modes are theoretically analyzed, and it is found that the coupling intensity described by the Bessel function and different polarizations of the two modes are the main reasons leading to the above phenomenon. The theoretical results of this study fit well with the simulated and numerical results.

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Progress and First Results With the New Multifrequency ECRH System for ASDEX Upgrade

Abstract: Abstract-

Cited by 16 publications

References 14 publications

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

A survey of electron Bernstein wave heating and current drive potential for spherical tokamaks

Electron Cyclotron Harmonic Wave Heating in Tokamak Plasmas with Different Polarization Modes

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