Experimental Study on Triggering Characteristics of a Surface Flashover Triggered Vacuum Switch

Yao, Xueling; Chen, Jingliang; Sun, Wei

doi:10.1088/1009-0630/12/6/17

Cited by 7 publications

(4 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experimental set-up of the SMBI system in the HL-2A tokamak is shown in [3]. The SMBI lies on the equatorial plane and is aimed perpendicular to the magnetic axis of HL-2A.…”

Section: Smbi Localized Boundary Conditionsmentioning

confidence: 99%

“…Plasma fuelling with higher efficiency and deeper injection is crucial to enable fusion power performance requirements at high density for next generation devices such as ITER. There are three major fuelling methods: gas puffing (GP) [1], pellet injection (PI) [2] and supersonic molecular beam injection (SMBI) [3]. The fuelling efficiency of GP is low because its injection depth is usually very shallow and most molecules are localized outside the magnetic separatrix (last closed flux surface-LCFS) near the edge of tokamak.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, SMBI enhances the particle injection depth and fuelling efficiency compared to GP, and its injection depth is also comparable to a small or low energy PI but costs less than a PI. There have been many experimental studies [3][4][5] to improve the penetration depth and fuelling efficiency of SMBI in the HL-2A tokamak, such as changing from low (magnetic) field side (LFS) injection to high (magnetic) field side (HFS) injection, varying the injection speed, temperature, and particle flux intensity. Besides being a fuelling method, SMBI is also a good tool for plasma density control [5], L-H transition and confinement improvements [6], edge localized mode (ELM) mitigation [7], and nonlocal heat transport [8] studies.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

2D simulations of transport dynamics during tokamak fuelling by supersonic molecular beam injection

Wang

Xia

et al. 2014

Nucl. Fusion

View full text Add to dashboard Cite

Time-dependent transport of both plasma and neutrals is simulated during supersonic molecular beam injection (SMBI) yielding the evolution of edge plasma and neutral profiles. The SMBI model is included as a module, called trans-neut, within the original BOUT++ boundary plasma turbulence code. Results of calculations are reported for the realistic divertor geometry of the HL-2A tokamak. The model can also be used to study the effect of gas puffing. A seven-field fluid model couples plasma density, heat, and momentum transport equations together with neutral density and momentum transport equations for both molecules and atoms. Collisional interactions between molecules, atoms, and plasma include dissociation, ionization, recombination and charge-exchange effects. Sheath boundary conditions and particle recycling are applied at both the wall and the divertor plates. A localized boundary condition of constant molecular flux (product of density times speed) is applied at the outermost flux surface to model the SMBI. Steady state profiles with and without particle recycling are achieved before SMBI. During SMBI, the simulation shows that neutrals can penetrate several centimetres inside the last closed (magnetic) flux surface (LCFS). Along the SMBI path, plasma density increases while plasma temperature decreases. The molecule penetration depth depends on both the SMBI flux and the initial plasma density and temperature along its path. As the local plasma density increases substantially, molecule and atom penetration depths decrease due to their higher dissociation and ionization rates if the electron temperature does not drop too low. Dynamic poloidal spreading of the enhanced plasma density region is observed due to rapid ion flow along the magnetic field (parallel) driven by a parallel pressure asymmetry during SMBI. Profile relaxation in the radial and poloidal directions is simulated after SMBI termination, showing that the plasma returns to pre-SMBI conditions on a time scale of 60 ms.

show abstract

“…The experimental set-up of the SMBI system in the HL-2A tokamak is shown in [3]. The SMBI lies on the equatorial plane and is aimed perpendicular to the magnetic axis of HL-2A.…”

Section: Smbi Localized Boundary Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

2D simulations of transport dynamics during tokamak fuelling by supersonic molecular beam injection

Wang

Xia

et al. 2014

Nucl. Fusion

View full text Add to dashboard Cite

show abstract

“…He pointed out that the arc resistance of tungsten alloy is better than that of copper alloy, molybdenum and copper [12]. References [13][14][15] conducted a comprehensive study on the erosion characteristics of tungsten-copper alloy electrodes. From the perspective of structure, researchers have studied the effects of the discharge tube's electrode gap and electrode structure on the breakdown voltage, the response time, the current capacity, and other discharge tube characteristics [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Reliability improvement of gas discharge tube by suppressing the formation of short-circuit pathways

Cheng¹,

Xiang²,

Li³

et al. 2022

Plasma Sci. Technol.

View full text Add to dashboard Cite

After cumulative discharge of gas discharge tube (GDT), it is easy to form a short circuit pathway between the two electrodes, which increases the failure risk and causes severe influences on the protected object. To reduce the failure risk of GDT and improve cumulative discharge times before failure, this work aims to suppress the formation of two short-circuit pathways by optimizing the tube wall structure, the electrode materials and the electrode structure. A total of five improved GDT samples are designed by focusing on the insulation resistance change that occurs after the improvement; then, by combining these designs with the microscopic morphology changes inside the cavity and the differences in deposition composition, the reasons for the differences in the GDT failure risk are also analyzed. The experimental results show that compared with GDT of traditional structure and material, the method of adding grooves at both ends of the tube wall can effectively block the deposition pathway of the tube wall, and the cumulative discharge times before device failure are increased by 149%. On this basis, when the iron-nickel electrode is replaced with a tungsten-copper electrode, the difference in the electrode’s surface splash characteristics further extends the discharge times before failure by 183%. In addition, when compared with the traditional electrode structure, the method of adding an annular structure at the electrode edge to block the splashing pathway for the particles on the electrode surface shows no positive effect, and the cumulative discharge times before the failure of the two structures are reduced by 22.8% and 49.7% respectively. Among these improved structures, the samples with grooves at both ends of the tube wall and tungsten-copper as their electrode material have the lowest failure risk.

show abstract

Research on the trigger process of surface flashover triggered vacuum switch

Zhang

Liao

Lü

et al. 2023

Vacuum

View full text Add to dashboard Cite

Experimental Study on Triggering Characteristics of a Surface Flashover Triggered Vacuum Switch

Cited by 7 publications

References 11 publications

2D simulations of transport dynamics during tokamak fuelling by supersonic molecular beam injection

2D simulations of transport dynamics during tokamak fuelling by supersonic molecular beam injection

Reliability improvement of gas discharge tube by suppressing the formation of short-circuit pathways

Research on the trigger process of surface flashover triggered vacuum switch

Contact Info

Product

Resources

About