High performance discharges near the operational limit in HT-7

Li, Jiangang; Wan, Baonian; Luo, Junhua; Gao, Xiang; Zhao, Yanping; Guang-li, Kuang; Zhang, Xiaodong; Yang, Yu; Yang, Bao; Ding, Bojiang; Xie, Jinbo; Wan, Yuanxi; Group, HT-7

doi:10.1088/0029-5515/41/11/312

Cited by 8 publications

(4 citation statements)

References 13 publications

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“…The lower hybrid current drive (LHCD) system consisted of a multijunction grill (4×12), a 1.2 MW wave system with a frequency of 2.45 GHz. Efforts have been made for steady state operation and many good results have been obtained during the past few years [11,12]. The longest plasma duration was over 300 s by LHCD with a central electron temperature of 1 keV.…”

Section: Experimental Set-up and Main Resultsmentioning

confidence: 99%

Quasi-steady-state ac plasma current operation in HT-7 tokamak

Luo²,

Wang³

et al. 2007

Nucl. Fusion

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A quasi-steady-state alternating current operation assisted by lower hybrid wave (LHW) was achieved on a HT-7 superconducting tokamak with plasma current of I p = 125 kA, line-averaged density of 1.5 × 1019 m−3, electron temperature of T e = 500 eV and 30–50 s plasma duration. Plasma current was sustained and smoothly transferred from one direction to the other without loss of ionization. Plasma position control, LHW assistance, strong gas puffing and good wall condition are the key issues to have a smooth transition of plasma current. Our modelling results show that current reversal equilibrium configuration with two oppositely flowing currents in the high-field-side and the low-field-side during current reversal exists. This is in agreement with experimental measurements.

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Section: Experimental Set-up and Main Resultsmentioning

confidence: 99%

Quasi-steady-state ac plasma current operation in HT-7 tokamak

Luo²,

Wang³

et al. 2007

Nucl. Fusion

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“…[11][12][13] It is not easy to get high performance steady-state H-mode in HT-7 due to several problems, such as magnetohydrodynamic ͑MHD͒ instability, high impurity radiation, and edge recycling. The features of IBW and LHCD are integrated to obtain long pulse high performance discharges by proper optimization of operation, particularly, choosing a strategy to avoid MHD activities.…”

Section: Resultsmentioning

confidence: 99%

Long pulse enhanced confinement discharges in the HT-7 superconducting tokamak by ion Bernstein wave heating and lower hybrid wave current drive

Wan

Luo

et al. 2003

Physics of Plasmas

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Significant progress has been made on the HT-7 superconducting tokamak (R=1.22 m, a=0.27 m) in the past year toward obtaining advanced operating modes in steady state. By combining ion Bernstein wave and lower hybrid current drive edge-localized-mode-free limiter H-mode discharges with H89∼2, βN*H89>3 have been obtained that lasted for 53 τE. A well-boronized wall prevented further impurity accumulation and the large pumping kept the recycling at a very low level. The density was kept almost constant with the feedback control. The noninductive driven current fraction is about 60% and bootstrap fraction is about 18%. The central electron temperature is about 2.6 keV and density above 2×1019 m−3. With reduced plasma parameters of central Te∼1.5 keV and ne0∼2×1019 m−3, H89∼1.45, βN∼1.1, the improved confinement phase lasts for more than 100 τE with the noninductive driven current fraction ∼70%.

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“…The important role of first wall conditioning in reducing plasma impurities has been recognized for decades and efforts have been made to control impurities in most tokamaks [19][20][21][22][23][24]. GDC boronization was used in EAST, and the plasma performance was improved afterwards.…”

Section: Gdc Boronization and Extended Limitsmentioning

confidence: 99%

“…Most of the stable sawtooth discharges were achieved after the second GDC boronization. The ICRF boronization technology [19,20] will be used in the next experimental campaign on EAST.…”

Section: Gdc Boronization and Extended Limitsmentioning

confidence: 99%

Extension of operational limits on EAST

Gao¹,

Li²,

Wan³

et al. 2007

Nucl. Fusion

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The first plasma has been achieved successfully in the Experimental Advanced Superconducting Tokamak (EAST). Boronization by the glow discharge (GDC) method was studied in experiments. The plasma performance was obviously improved by GDC boronization. Extension of the operational region and improvement in the plasma performance were obtained. Sawtooth discharges were observed by means of soft x-ray signals, electron cyclotron emission signals and line averaged electron density after boronization. Lower qa and more stable operation were also achieved following GDC boronization. The plasma current ramp-up rate was also improved as a result of decreased impurity content and low averaged loop voltage due to boronization. PLEASE NOTE: THERE HAS BEEN A RETRACTION PUBLISHED FOR THIS ARTICLE.

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High performance discharges near the operational limit in HT-7

Cited by 8 publications

References 13 publications

Quasi-steady-state ac plasma current operation in HT-7 tokamak

Quasi-steady-state ac plasma current operation in HT-7 tokamak

Long pulse enhanced confinement discharges in the HT-7 superconducting tokamak by ion Bernstein wave heating and lower hybrid wave current drive

Extension of operational limits on EAST

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