High-power tests of a remote steering launcher mock-up at 140 GHz

Plaum, B.; Gantenbein, G.; Kasparek, W.; Schwörer, K.; Grünert, M.; Braune, H.; Erckmann, V.; Hollmann, Frank; Jonitz, L.; Laqua, H. P.; Michel, G.; Noke, F.; Purps, F.; Bruschi, A.; Cirant, S.; Gandini, F.; Verhoeven, A.G.A.

doi:10.1088/1742-6596/25/1/016

Cited by 13 publications

(5 citation statements)

References 8 publications

(6 reference statements)

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“…In a RSA the beam convergence and the polarization at the waveguide input are preserved at its output. Tests of RSAs have been already successfully performed both at low power [24] and at MW power level [25]. The steering range available, ϕ ∼ = 0-11 • in asymmetric RSAs and ϕ ∼ = ±(10 • -20 • ) in symmetric RSAs [26], is adequate for the CTS needs since the only constraint from being strictly satisfied, possible geometrical restrictions apart, is avoiding the scattering plane from being purely poloidal.…”

Section: Discussionmentioning

confidence: 99%

Critical issues highlighted by collective Thomson scattering below electron cyclotron resonance in FTU

Tartari¹,

Grosso²,

Granucci³

et al. 2006

Nucl. Fusion

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Strong anomalous spectra were systematically observed in collective Thomson scattering (CTS) at 140 GHz in the high-field tokamak FTU, a proof-of-principle experiment of CTS on thermal density fluctuations performed with propagation below electron cyclotron (EC) resonance with the final aim of demonstrating high-density CTS in the extraordinary mode. Following the results of two experimental campaigns expressly performed to investigate them, these spectra are ascribed to a gyrotron perturbation caused by a back-reflected signal originating in the beam injection port, where the electron cyclotron layer, the upper-hybrid layer and the right-handed cutoff layer unavoidably crossed by the probing beam are activated by a breakdown plasma sustained by the beam itself. The degree of generality ascribable to our results and the constraints they set on present and future CTS experiments with propagation below electron cyclotron resonance are discussed. A viable solution in terms of a transmit antenna robust against the risk of gyrotron perturbation is suggested.

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Section: Discussionmentioning

confidence: 99%

Critical issues highlighted by collective Thomson scattering below electron cyclotron resonance in FTU

Tartari¹,

Grosso²,

Granucci³

et al. 2006

Nucl. Fusion

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“…One possible splitter available is the square or rectangular corrugated waveguide of length L = 2D 2 /λ where D is the waveguide aperture and λ the wavelength. Its length is half of that of a remote steering antenna, which has already been studied and tested at high power [23,24]. When one beam is launched at the input with angular (with angle less than a few degrees) or side input (figure 11(a)), two beams of equal (half) power emerge from the waveguide output.…”

Section: Other Versions Of Resonant Diplexers-combinermentioning

confidence: 99%

A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

Kasparek¹,

Petelin²,

Shchegolkov³

et al. 2008

Nucl. Fusion

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Abstract.A fast directional switch (FADIS) is described, which allows controlled switching of high-power microwaves between two outputs. A possible application could be synchronous stabilization of neoclassical tearing modes (NTM). Generally, the device can be used to share the installed EC power between different types of launchers or different applications (e.g. in ITER, midplane / upper launcher). The switching is performed electronically without moving parts by a small frequency-shift keying of the gyrotron (some tens of MHz), and a narrow-band diplexer. The device can be operated as a beam combiner also, which offers attractive transmission perspectives in multi-megawatt ECRH systems. In addition, these diplexers are useful for plasma diagnostic systems employing high-power sources due to their filter characteristics. The principle and the design of a four-port quasi-optical resonator diplexer is presented. Lowpower measurements of switching contrast, mode purity and efficiency show good agreement with theory. Preliminary frequency modulation characteristics of gyrotrons are shown, and first results from high-power switching experiments using the ECRH system for W7-X are presented.

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“…±15º) steering range with no movable parts or mirrors in plasma proximity, but recessed out of the port. The option has been extensively studied during ITER ECRH Upper Launcher Design [15] and the implemented in the EC Launcher of the W7-X stellarator [16].…”

Section: -3mentioning

confidence: 99%