ICRF antenna impedance measurements with voltage and current probes on EAST

Wang, J.H.; Chen, G.; Zhao, Yanping; Mao, Yuzhou; Yuan, Shuai; Zhang, X.J.; Bernard, J. M.; Lombard, G.; Helou, W.; Chen, Zhiwen; Urbanczyk, G.; Qin, Chengming; Cheng, Yan; Yang, Hua; Zhang, J.H.; Yang, Yong; Zhang, Kui; Ju, SQ; Deng, Xu; Wan, Baonian; Gong, X.Z.; Li, J.G.; Hu, Liqun; Song, Yuntao

doi:10.1016/j.fusengdes.2017.08.018

Cited by 8 publications

(11 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A3) [1,3,23]. The power lost in the transmission line is not measured experimentally, however calculation of the RF losses show that they are always less than 15%, resulting from uncertainties on power estimations detailed in [24]. In addition, the phase between straps cannot be changed in real time [25].…”

Section: Experimental Conditions and Protocol In Eastmentioning

confidence: 99%

Metallic impurity content behavior during ICRH-heated L-mode discharges in EAST

Urbanczyk¹,

Zhang²,

Zhang³

et al. 2020

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de

show abstract

Section: Experimental Conditions and Protocol In Eastmentioning

confidence: 99%

Metallic impurity content behavior during ICRH-heated L-mode discharges in EAST

Urbanczyk¹,

Zhang²,

Zhang³

et al. 2020

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

show abstract

“…Mostly to simplify the analysis of the edge diagnostics data, but also because EAST ICRF system [13] does not have very strong load resilience, operations in H-mode are not appropriate to the present study which is performed in L-mode. The EAST ICRF antenna loading can be estimated by two different methods respectively based on voltage/current probes [13] and voltage probe arrays [14]. In this paper we will use the second technique which often gives more accurate results; for each shot, the maximum voltage V max is measured with voltage probe arrays in different points of each transmission lines of characteristic impedance Z 0 as shown on Fig.…”

Section: Presentation Of East Parameters and Diagnostics Used In Thismentioning

confidence: 99%

“…In the present study, we did not try to mitigate the influence that gas puffing may have on H-mode pedestals, but choose to focus on its influence on the edge in absence of ELMs. Mostly to simplify the analysis of the edge diagnostics data, but also because EAST ICRF system [13] does not have very strong load resilience, operations in H-mode are not appropriate to the present study which is performed in L-mode.…”

Section: Presentation Of East Parameters and Diagnostics Used In This...mentioning

confidence: 99%

“…The EAST ICRF antenna loading can be estimated by two different methods respectively based on voltage/current probes [13] and voltage probe arrays [14]. In this paper we will use the second technique which often gives more accurate results; for each shot, the maximum voltage V max is measured with voltage probe arrays in different points of each transmission lines of characteristic impedance Z 0 as shown on figure 2-respectively near the stub tuner and the antenna.…”

Section: Presentation Of East Parameters and Diagnostics Used In This...mentioning

confidence: 99%

See 1 more Smart Citation

Optimization of discharges with ion cyclotron range of frequencies using local gas injection in EAST

et al. 2019

Self Cite

View full text Add to dashboard Cite

In view of improving Ion Cyclotron Range of Frequencies (ICRF) wave coupling in EAST (Experimental Advanced Superconducting Tokamak) necessary to obtain high-power discharges, two series of experiments in L-mode were devoted to the use of local gas injection as a tool to increase density in front of the antennas.During the first session, the quantity of deuterium simultaneously puffed from five different poloidal positions on each side of one ICRF antenna was gradually increased. Steady gas puffing on this antenna (~8.10 20 e/s) increased antenna coupling resistance by 100%, but puffing more gas did not provoke any further improvement.Plasma central electron density was not kept constant when using local puff but kept increasing during the discharges. During the second session, the global density was well-controlled and remained constant, the distance between the separatrix and the first wall was increased by 2cm allowing, the gas to spread better, and puffing more gas this time lead to better wave coupling. The same amount of gas was then puffed from three different locations and changes in SOL (Scrape-Off Layer) parameters were measured from several locations. Extensive analysis of the edge diagnostics made it possible to observe an electron density increase and a temperature decrease caused by the ionization of neutrals in the SOL. Heat loads on the divertor targets were slightly mitigated by gas injection, which is favorable from the perspective of long pulse scenario development. Injection at mid-plane led to the best results with the highest coupling simultaneously achieved for both antennas and smallest heat loads on the divertor target (below 1MW/m²). As far as wave coupling efficiency is concerned, most experimental trends were also successfully reproduced by antenna modelling with the RAPLICASOL finite element code with experimental density profiles from reflectometry as the main input.

show abstract

“…The absolute deviations seem large for some small loads, this is mainly due to the phase measurement error. The phase measurement error leads to large deviation of coupling resistance calculation, while the amplitude measurement error has gentle impact on resistance [5]. The most principal issue for V/I measurement is the accurate phase measurement.…”

Section: Measurement Results From the Testing Platformmentioning

confidence: 99%

Design and test of voltage and current probes for EAST ICRF antenna impedance measurement

Wang

Chen

Zhao

et al. 2018

Plasma Sci. Technol.

View full text Add to dashboard Cite

On the experimental advanced superconducting tokamak (EAST), a pair of voltage and current probes (V/I probes) is installed on the ion cyclotron radio frequency transmission lines to measure the antenna input impedance, and supplement the conventional measurement technique based on voltage probe arrays. The coupling coefficients of V/I probes are sensitive to their sizes and installing locations, thus they should be determined properly to match the measurement range of data acquisition card. The V/I probes are tested in a testing platform at low power with various artificial loads. The testing results show that the deviation of coupling resistance is small for loads R L >2.5 Ω, while the resistance deviations appear large for loads R L <1.5 Ω, which implies that the power loss cannot be neglected at high VSWR. As the factors that give rise to the deviation of coupling resistance calculation, the phase measurement error is the more significant factor leads to deleterious results rather than the amplitude measurement error. To exclude the possible ingredients that may lead to phase measurement error, the phase detector can be calibrated in steady L-mode scenario and then use the calibrated data for calculation under H-mode cases in EAST experiments.

show abstract

ICRF antenna impedance measurements with voltage and current probes on EAST

Cited by 8 publications

References 9 publications

Metallic impurity content behavior during ICRH-heated L-mode discharges in EAST

Metallic impurity content behavior during ICRH-heated L-mode discharges in EAST

Optimization of discharges with ion cyclotron range of frequencies using local gas injection in EAST

Design and test of voltage and current probes for EAST ICRF antenna impedance measurement

Contact Info

Product

Resources

About