Designing an upgrade of ohmic heating system for the QUEST spherical tokamak

Zhang, Yifan; Onchi, Takumi; Nakamura, K.; Kidani, Akihiro; Yue, Qilin; Kuroda, Kengoh; Hasegawa, Makoto; Ikezoe, Ryuya; Idei, H.

doi:10.1016/j.fusengdes.2021.112362

Cited by 3 publications

(1 citation statement)

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“…56 GHz EC wave. Our approach is based on enhancing the OH by doubling the flux swing [20]. Two high-power current sources are combined using two switches comprising 2×2 insulated-gate bipolar transistor (IGBT) stacks and a diode stack.…”

Section: Introductionmentioning

confidence: 99%

Initial testing of ohmic heating through double flux swing during electron cyclotron start-up in the QUEST spherical tokamak

Zhang

Onchi

Nakamura

et al. 2023

Plasma Sci. Technol.

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For the QUEST spherical tokamak, we developed a power-supply system for ohmic heating (OH) to double the amount of change in the coil current of the primary central solenoid (CS). Two power supplies are connected with stacks of insulated-gate bipolar transistors and sequentially operated to generate positive and negative CS currents. This bipolar power-supply system is controlled via a field-programmable gate array (FPGA), which guarantees the safety of the entire system operation. The new OH system, assisted by electron cyclotron (EC) heating, enables the stable generation of plasma currents exceeding 100 kA. Moreover, the achieved electron density over the wide range in the major radial direction exceeds the cut-off density for one of the high-power microwave sources in QUEST. Notably, this strategy yields target plasmas for future experiments with the electron Bernstein wave.

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Section: Introductionmentioning

confidence: 99%