Design of a PAM launcher and comparative analysis with the old FAM launcher for 2.45 GHz LHCD system on EAST

Li, M.H.; Liu, L.; Tang, Yunying; Wang, M.; Zhao, Liang; Liu, F.K.; Shan, Jiafang; Ding, Bojiang; Jia, H.; Xu, H.; Wang, X.J.; Wu, Dajun; Wu, Zhenwei; Hillairet, J.; Goniche, M.; Delpech, L.; Peysson, Y.

doi:10.1016/j.fusengdes.2019.111250

Cited by 7 publications

(8 citation statements)

References 20 publications

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“…In summary, for optimum coupling, the distance of the 2.45 GHz PAM to the plasma can be ∼2 cm longer than the 2.45 GHz FAM, and 4 cm longer than the 4.6 GHz FAM, respectively. As shown in [20], the density at the antenna mouth for optimum coupling for 2.45 GHz PAM lies slightly below the cut-off density (n e_co = 0.74 × 10 17 m −3 ), namely, around 0.5 × 10 17 m −3 . Regarding the 4.6 GHz FAM with n e_co = 2.6 × 10 17 m −3 , the density for optimum coupling is about 10 × 10 17 m −3 , according to the previous modeling in [21].…”

Section: Coupling Characteristicsmentioning

confidence: 90%

“…The PAM launcher was constructed based on the optimized design in [20]. As shown in figure 1, the whole PAM launcher consists of the multijunction at the front, the straight waveguides in the middle, and the transitional waveguides at the rear.…”

Section: Description Of the Pam Launchermentioning

confidence: 99%

“…The dimension of the cooling ducts is 12 mm × 12 mm, which is realized by brazing two symmetric stainless steel plates. Calculations indicate that the maximum temperature at the front surface is only ∼260 • C with the assumption of 0.15 MW m −2 heat flux from plasmas radiation and 3.5 kW m −2 heat flux from RF losses [20]. The guard limiters at both sides are also actively cooled with tungsten material and protrude 2-3 mm from the PAM surface to reduce heat load from the plasma (see figure 1(c)).…”

Section: Description Of the Pam Launchermentioning

confidence: 99%

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First experimental results of the PAM LHCD launcher at 2.45 GHz on EAST

Li¹,

Liu²,

Wang³

et al. 2023

Nucl. Fusion

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This paper presents the first results of a passive active multijunction (PAM) launcher at 2.45 GHz during the lower hybrid current drive (LHCD) experiments on EAST. Good coupling performance with a power reflection coefficient (RC) ~ 3% has been achieved at the plasma-antenna distance up to ~ 11 cm in L-mode edge plasmas without local gas puffing near the PAM launcher. Reliable power coupling of this PAM during the edge perturbations induced by type I ELMs has been successfully demonstrated. Compared with the old full active multijunction (FAM) launcher, the new PAM can be placed ~ 2 cm further away from the plasma in normal operations, which is in good agreement with the previous prediction (Li et al. 2019 Fusion Eng. Des. 147 111250), by the linear wave-plasma coupling code ALOHA (Hillairet et al. 2010 Nucl. Fusion 50 125010). The flexibility of the power spectrum by changing the phase difference between adjacent modules was validated and ray-tracing / Fokker-Planck simulations can reproduce the experimental features. The achievable power handling is as high as 25 MW m-2, although with a shot pulse length of ~ 10 s. The first experiment successfully demonstrated the coupling performance of a PAM launcher at low density and this launcher construction provides helpful engineering experience for the 4.6 GHz PAM development in the near future on EAST.

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Section: Coupling Characteristicsmentioning

confidence: 90%

Section: Description Of the Pam Launchermentioning

confidence: 99%

Section: Description Of the Pam Launchermentioning

confidence: 99%

See 1 more Smart Citation

First experimental results of the PAM LHCD launcher at 2.45 GHz on EAST

Li¹,

Liu²,

Wang³

et al. 2023

Nucl. Fusion

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“…EAST is a divertor configuration tokomak with a minor radius a = 0.45 m and major radius R = 1.85 m. At this stage, EAST is equipped with 4 MW/2.45 GHz LHW [26], 6 MW/4.6 GHz LHW [27], 1 MW/140 GHz ECH [28,29] and 12 MW/25-70 MHz ICRF systems [22]. The layout of RF wave systems on EAST is shown in figure 1.…”

Section: Rf Systems and Diagnostics Systems On Eastmentioning

confidence: 99%

Overview of the ICRF antenna coupling experiments on EAST

et al. 2021

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Experimental verification of ion cyclotron range of frequencies (ICRF) wave coupling is crucial to gain insight into the physics of the improvement of ICRF antenna coupling. The progress of ICRF antenna coupling experiments on EAST has been reported since 2007. The dependence of the loading resistance on the target plasma parameters, operational regimes and synergic heating scenarios on EAST are reviewed. Results show that the antenna coupling resistance R c in L-mode regime meets the relation of R c ∝ exp(−1.5k ∥ x c), which is in good agreement with the simulation results with a perfectly matched layer method, where k ∥ is the dominant launched parallel wave number and x c is the distance of the ICRF antenna and fast wave cut-off layer. Low plasma current, gas puff in the magnetic connections with the ICRF antenna and lower hybrid wave/electron cyclotron heating are beneficial for improving ICRF antenna coupling. The antenna coupling has a strong response during large edge-localized modes (ELMs) but it becomes steady state during ELM free. The study of ICRF antenna coupling under various parameters is helpful to optimize the ICRF wave heating scenario and understand the physical mechanisms which influence the ICRF wave coupling in plasmas.

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“…Experimental advanced superconducting tokamak (EAST) [1], the first fully superconducting tokamak, aims at high performance and long pulse operation up to 1000 s. Lower hybrid current drive (LHCD) has been a very important method to realize the design goal in EAST [2]. There are two LHCD systems operating at 2.45 GHz [3,4] and 4.6 GHz [5,6] respectively. Various physics experiments require different lower hybrid wave (LHW) power modes.…”

Section: Introductionmentioning

confidence: 99%

Development of lower hybrid wave power feedback control and experiments on EAST

Wang

Yang

et al. 2023

J. Inst.

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A new method of power feedback control for the lower hybrid wave (LHW) systems on the experimental advanced superconducting tokamak (EAST) is presented. Different methods are applied to control the power of two LHW systems with different frequency at 2.45 GHz and at 4.6 GHz, respectively. The old method is applied to control the 4.6 GHz LHW power through the exciter of klystrons, and the new one is used to control the 2.45 GHz LHW power through the high voltage power supply (HVPS) system. The new method has been applied in EAST and successfully assisted the development of relevant experiments such as loop voltage control, q profile control.

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Design of a PAM launcher and comparative analysis with the old FAM launcher for 2.45 GHz LHCD system on EAST

Cited by 7 publications

References 20 publications

First experimental results of the PAM LHCD launcher at 2.45 GHz on EAST

First experimental results of the PAM LHCD launcher at 2.45 GHz on EAST

Overview of the ICRF antenna coupling experiments on EAST

Development of lower hybrid wave power feedback control and experiments on EAST

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