Investigation of the compact torus plasma motion in the KTX-CTI device based on circuit analyses

Dong, Qilong; Kong, Defeng; Wu, Xiaoxiao; Ye, Yang; Yang, Kun; Lan, Tao; Chen, Chen; Wu, Jie; Zhang, Sen; Mao, Wenzhe; Zhao, Zhihao; Meng, Fanwei; Zhang, Xiaohui; Huang, Yuanqing; Bai, Wei; Yang, Dezheng; Wen, Fei; Zi, Pengfei; Li, Lei; Hu, G.H.; Zhang, Shoubiao; Zhuang, G.

doi:10.1088/2058-6272/ac446e

Cited by 3 publications

(4 citation statements)

References 37 publications

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“…Normally, the initial magnetic moment direction and the initial velocity direction of the CT are either the same or opposite. Parallel injection and antiparallel injection can be achieved by controlling the current direction in a solenoid coil in the formation region of the CT injector [17].…”

Section: ẏI τ ρmentioning

confidence: 99%

“…Notably, tangential CT injection into the STOR-M tokamak can induce H-mode-like discharges [15]. Furthermore, CT technology can be applied to field-reversed configuration (FRC) and reversed field pinch (RFP) devices, such as the C-2 and Keda Torus eXperiment (KTX) devices [16][17][18]. The discharge parameters of the HL-2A device are very close to those of the KTX device.…”

Section: Introductionmentioning

confidence: 96%

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Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma

DONG 董,

ZHANG 张,

LAN 兰

et al. 2024

Plasma Sci. Technol.

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The trajectory of the compact torus (CT) within a tokamak discharge is crucial to fueling. In this study, we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tokamak discharges. This model was used to calculate the trajectory and penetration parameters of CT injections by applying both perpendicular and tangential injection schemes in both HL-2A and ITER tokamaks. For perpendicular injection along the tokamak's major radius direction from the outboard, CTs with the same injection parameters exhibited an 0.08 reduction in relative penetration depth when injected into HL-2A and a 0.13 reduction when injected into ITER geometry when considering the vacuum magnetic field region compared with cases where this region was not considered. In addition, we proposed an optimization method for determining the CT's initial injection velocity to accurately calculate the initial injection velocity of CTs for central fueling in tokamaks. Furthermore, this paper discusses schemes for the tangential injection of CT into tokamak discharges. The optimal injection angle and CT magnetic moment direction for injection into both HL-2A and ITER were determined through numerical simulations. Finally, the kinetic energy loss occurring when the CT penetrated the vacuum magnetic field region in ITER was reduced by ΔEk=975.08J by optimizing the injection angle for the CT injected into ITER. These results provided valuable insights for optimizing injection angles in fusion experiments. Our model closely represents actual experimental scenarios and can assist the design of CT parameters.

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Section: ẏI τ ρmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma

DONG 董,

ZHANG 张,

LAN 兰

et al. 2024

Plasma Sci. Technol.

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“…The evaluation of the inner radius depends on the simulation of the 1D point model [6]. The result of the point model showed that the energy utilization rate of the power supply improved with the increase in the ratio of the outer radius to the inner radius (r o_acc /r i_acc ) [22], i.e., a very low value of r i_acc was favorable. However, a very small value of r i_acc increases the chamber volume, thereby diluting the density and magnetic field strength of the plasma.…”

Section: Acceleration Regionmentioning

confidence: 99%

“…Moreover, in the small r i_acc case, the toroidal field induced by the discharge current along the acceleration inner electrode may be an uneven distribution, resulting in a large gradient of J×B force in the r direction, and the blowby effect can occur near the inner electrode, which is unfavorable for CT plasma [23]. Considering the energy utilization rate, density uniformity, and lifetime of the CT plasmoid, we set the r o_acc /r i_acc of EAST-CTI as 2.9 [22].…”

Section: Acceleration Regionmentioning

confidence: 99%

Design and platform testing of the compact torus central fueling device for the EAST tokamak

Kong

Zhuang

Lan

et al. 2023

Plasma Sci. Technol.

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Compact Tours (CT) injection is a highly promising technique for the central fueling of future reactor-grade fusion devices since it features extremely high injection velocity and relatively high plasma mass. Recently, a CT injector for the EAST tokamak, EAST-CTI, was developed and platform-tested. In the first round of experiments conducted with low parameter settings, the maximum velocity and mass of the CT plasma were 150 km·s−1 and 90 µg, respectively. However, the parameters obtained by the EAST-CTI were still very low and were far from the requirements of a device such as the EAST that has a strong magnetic field. In the future, we plan to solve the spark problem that the EAST-CTI currently encounters (that mainly hinders the further development of experiments) through engineering methods and use greater power to obtain a more stable and suitable CT plasma for EAST.

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Theory and simulation of the force-free equilibria in the EAST-CTI

Huang

Kong

Xia

et al. 2023

Plasma Phys. Control. Fusion

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Compact torus injection (CTI) is a novel approach to fueling the core of a fusion reactor. In this paper, the force-free equilibrium based on the EAST-CTI is calculated. It is found that the α, which is proportional to the ratio of the toroidal current to the toroidal magnetic field, plays a key role for the force-free equilibrium. When it is smaller than the eigenvalue, the open poloidal magnetic flux decreases while the magnetic field strength increases as its value increases. However, once α equals the eigenvalue, the amplitude of the magnetic field tends to infinity and the boundary magnetic field is tangential to the wall. In addition, in this work we found that the eigenvalue is mainly determined by the width of the formation region, enlarging the width will significantly reduce the eigenvalue and further affecting the CT formation. Another interesting phenomenon in this work is that the poloidal magnetic field plays a hindering role in the formation of CT, and theoretically, CT is difficult to detach from the forming region when α'(α^'~J_p/B_p) is less than the threshold α_c. In experiments, we show that a discharge with α'<α_c leads to an increased delay between the onset of the current in the acceleration and formation regions. These findings provide some guidance for the carrying out of the experiments and future modifications of the device.

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Investigation of the compact torus plasma motion in the KTX-CTI device based on circuit analyses

Cited by 3 publications

References 37 publications

Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma

Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma

Design and platform testing of the compact torus central fueling device for the EAST tokamak

Theory and simulation of the force-free equilibria in the EAST-CTI

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