High field side measurements of non-thermal electron cyclotron emission on TCV plasmas with ECH and ECCD

Blanchard, P.; Alberti, S.; Coda, S.; Weisen, H.; Nikkola, P.; Klimanov, I.

doi:10.1088/0741-3335/44/10/310

Cited by 44 publications

(47 citation statements)

References 22 publications

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“…The best focusing, considering 1/e 2 width in intensity, is obtained for the LFS ECE at r/a = 0.6 and is less than 2 cm. [6] [7] 3. Correlation ECE The correlation ECE system in TCV was installed in 2007 but only with the last upgrade did it acquire an independent front end from the LFS ECE.…”

Section: Capabilitiesmentioning

confidence: 99%

Electron Cyclotron Emission (Ece) And Correlation Ece Diagnostic On Tcv

Fontana¹,

Porte²,

Marmillod³

2016

Proceedings of 1st EPS Conference on Plasma Diagnostics — PoS(ECPD2015)

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The electron cyclotron emission (ECE) and correlation ECE diagnostics in TCV have been upgraded during its 2014 shutdown; this paper will provide a brief overview on their updated architecture and capabilities. The ECE system is equipped with two radiometers, each with 24 channels (750 MHz bandwidth) looking at the plasma both from the low and high field side covering the whole vessel. Of particular interest is the possibility of acquiring signals through a vertical line of sight and a two-axis steerable antenna to study electron distribution function (EDF) in plasmas with ECCD or ECRH. The correlation ECE system has been equipped with a new independent front end connected to the steerable antenna. The main characteristics of the radiometer are the six YIG independently tunable (between 6-18 GHz) 170 MHz bandwidth channels that can be moved on the whole LFS of the vessel. Using correlation analysis techniques it is possible to study very small temperature fluctuations. A brief presentation of some applications where these capabilities have been exploited in past TCV experiments for the study of micro instabilities characteristics is also included.

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Section: Capabilitiesmentioning

confidence: 99%

Electron Cyclotron Emission (Ece) And Correlation Ece Diagnostic On Tcv

Fontana¹,

Porte²,

Marmillod³

2016

Proceedings of 1st EPS Conference on Plasma Diagnostics — PoS(ECPD2015)

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“…The expectation, guided also by previous results [13], is that a positive synergy would be mediated by a suprathermal electron population generated by 2 nd harmonic wave-plasma interaction. A significant suprathermal population is invariably observed whenever 2 nd harmonic waves are injected in ECCD mode, i.e., with a finite parallel wave number [6,14]. For this reason, the EC beams in the experiment under discussion were injected with a 16 o toroidal angle.…”

Section: Methodsmentioning

confidence: 99%

3rd harmonic electron cyclotron resonant heating absorption enhancement by 2nd harmonic heating at the same frequency in a tokamak

Gnesin

Decker

Coda

et al. 2012

Plasma Phys. Control. Fusion

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Abstract.The fundamental mechanisms responsible for the interplay and synergy between the absorption dynamics of extraordinary-mode electron cyclotron waves at two different harmonic resonances (the 2 nd and 3 rd ) are investigated in the TCV tokamak. An enhanced 3 rd harmonic absorption in the presence of suprathermal electrons generated by 2 nd harmonic heating is predicted by Fokker-Planck simulations, subject to complex alignment requirements in both physical space and momentum space. The experimental signature for the 2 nd /3 rd harmonic synergy is sought through the suprathermal bremsstrahlung emission in the hard X-ray range of photon energy. Using a synthetic diagnostic, the emission variation due to synergy is calculated as a function of the injected power and of the radial transport of suprathermal electrons. It is concluded that in the present experimental setup a synergy signature has not been unambiguously detected. The detectability of the synergy is then discussed with respect to variations and uncertainties in the plasma density and effective charge in view of future optimised experiments. 2nd -3 rd harmonic ECRH synergy 2

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“…The beam width changes by ≈ 5%, with divergence of ≈ 1 0 within the plasma position, as estimated by a calculation done in vacuum, using the Gaussian beam propagation equation. The signal collected by the antenna is transported by a circular waveguide of diameter of 2.5 cm to the radiometers, which can be used to measure second and third harmonics emission in the frequency range of 65-114.5 GHz, with bandwidth of either 750 MHz or 1.5 GHz [4] . The signals are digitized at a rate of 200 KHz.…”

Section: Vertical Ece Diagnostic On Tcvmentioning

confidence: 99%

Vertical Electron Cyclotron Emission Diagnostic for TCV Plasmas

Eshetua

Porte

Fasoli

et al. 2012

EPJ Web of Conferences

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Abstract. Electron cyclotron resonance heating (ECRH) and electron cyclotron current drive (ECCD) are used to heat the plasma, to tailor the current profiles and to achieve different operating regimes of tokamak plasmas. Plasmas with ECRH/ECCD are characterized by non-thermal electrons, which cannot be described by a Maxwellian distribution. Non-thermal electrons are also generated during MHD activity, like sawteeth crashes. Quantifying the non-thermal electron distribution is therefore a key for understanding EC heated fusion plasmas. For this purpose a vertical electron cyclotron emission (V-ECE) diagnostic is being installed at TCV. The diagnostic layout, the calibration, the analysis technique for data interpretation, the physics potentials and limitations are discussed.

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High field side measurements of non-thermal electron cyclotron emission on TCV plasmas with ECH and ECCD

Cited by 44 publications

References 22 publications

Electron Cyclotron Emission (Ece) And Correlation Ece Diagnostic On Tcv

Electron Cyclotron Emission (Ece) And Correlation Ece Diagnostic On Tcv

3rd harmonic electron cyclotron resonant heating absorption enhancement by 2nd harmonic heating at the same frequency in a tokamak

Vertical Electron Cyclotron Emission Diagnostic for TCV Plasmas

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