Current sheet characteristics of a parallel-plate electromagnetic plasma accelerator operated in gas-prefilled mode

Liu, Shuai; Huang, Yan; Guo, Heng; Lin, Ting; Huang, Dong; Yang, Lanjun

doi:10.1063/1.5004115

Cited by 9 publications

(3 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The discharge mode of the gun in this experiment is prefilled mode [20][21][22][23]. The pressure sensor (PCB 113B21) is used to measure the air pressure signal at the muzzle position, and the current probe is used to measure the current signal in the discharge process.…”

Section: Methodsmentioning

confidence: 99%

Experimental study on plasma generated by a tapered coaxial accelerator and its damage effects on a tungsten target at different angles

Zhao¹,

Chen²,

Song³

et al. 2022

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Plasma wall interaction (PWI) will occur inevitably during the operation of Tokamak. The coxial gun device has low operation cost and parameters of plasma produced by the gun are close to those of type I ELM, therefore, the coaxial gun is suitable in simulation experiment as heat-flux sources of transient events such as type I ELM under the condition of H-mode in ITER. In this paper, the plasma generated by the discharge of a tapered coaxial accelerator thermal shock on a tungsten target to simulate the damage effect of the divertor. The plasma parameters are measured in the experiment. The velocity of the plasma is 41.7 km/s, and the kinetic energy of a single hydrogen ion is 9.2 eV. The energy density at the center of the plasma can reach 1.5 MJ/m2, and the density can reach about 2.78×1015 /cm3. The reflection of plasma in the process of exposure at different angles is observed. It is observed that droplets of millimeter size splash from the target. Traces of liquid flow are observed on the surface of the target, which shows that there is a melting process on the surface of target. The mass loss of the target is in the order of mg after 20 pules. The ablation and residual stress of the target surface both decrease with the decrease of the angle. This is because the accumulated energy per unit area of the target surface decreases with the decrease of the angle. These results help us to better understand the damage effect of tungsten target for further research.

show abstract

Section: Methodsmentioning

confidence: 99%

Experimental study on plasma generated by a tapered coaxial accelerator and its damage effects on a tungsten target at different angles

Zhao¹,

Chen²,

Song³

et al. 2022

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

show abstract

“…Lee模型 [19] 仿真时将电流泄漏系数设在60%-70%范围内 [20,21] . 本课题组 [22] 在静态气压下采用方波电流研究了电流泄漏随气压和电流的变化, 发现初始气压越低, 放电电流越大, 电流泄漏比例越大, 这将导致等离子体速度随电流或气压非线性变化.…”

Section: 的条件下也发现了电流泄漏现象且许多学者采用unclassified

Current distribution and plasma velocity characteristics of parallel-plate accelerator under static pressure

Liu¹,

Xu²,

Liu³

et al. 2023

Acta Phys. Sin.

Self Cite

View full text Add to dashboard Cite

In the shallow water waveguide, matched field tracking methods use the continuity of the peak position of the moving source and the disorder of pseudo-peaks on the sequential ambiguity surfaces to track the underwater source trajectory. However, due to the dual influence of the space-time fluctuating shallow water waveguide environment and the complex sources motion scene, the existing matching field tracking methods are prone to track interruption, switches and false track phenomena, leading to discontinuous tracking results. Using the consistency of the peak position distance likelihood and peak amplitude likelihood of sequential ambiguity surfaces, a continuous matched field tracking method is proposed based on the trajectory Poisson multi-Bernoulli mixture filter in this paper. The proposed method is applied to SWellEx-96 experimental data and the tracking performance is measured by the linear programming metric. The results show that compared with the existing matching field tracking and multi-target tracking methods via random finite set, the proposed method achieves continuous tracking and accurate quantity estimation of moving sources trajectory. Among them, the prediction and updating steps in the trajectory space can avoid the phenomenon of trajectories interruption and switches in unvoiced periods. the prediction and updating steps in the trajectory space can avoid the phenomenon of trajectories interruption and switches in unvoiced periods.

show abstract

“…The canting current sheet then develops an axial component which produces a Lorentz force with a radial outward component, resulting in an accumulation effect of plasma mass in the cathode region [30,31]. Using photodiodes and optical emission spectrum, Liu et al [32,33] performed the measurement of the current sheet velocity and electron density at different propagation distances in a parallel-plate electromagnetic plasma accelerator. In addition, Poehlmann and Rieker et al [34,35] at Stanford University characterized the dynamics of the current distribution within the interior of a coaxial plasma gun and observed the evolution of the plasma operating in both the prefilled and gas-puff modes.…”

Section: Introductionmentioning

confidence: 99%

Effects of bias magnetic field on plasma ejection and dynamic characteristics of a coaxial gun operated in gas-puffed mode

Qi¹,

Song²,

Zhao³

et al. 2021

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

The effects of bias magnetic field on the discharge characteristics of a coaxial gun and the parameters of ejected plasma are studied. At constant initial conditions (charging voltage, gas-puffed), magnetic probe data at different axial positions reveal the influence of the external bias magnetic field on the current distribution within the annular flow channel. Both photodiode signals and plasma radiation images show the plasma ejection characteristics. It is found that either applying or not applying the bias magnetic field results in two types of plasma with distinct ejection characteristics: spheromak or jet. By comparing the plasma parameters with and without bias magnetic field, it is found that the variation of jets velocity and momentum with discharge conditions are consistent with the snowplow model, whereas the spheromak plasma is subjected to a retarding force −J ϕ B r ⇀ z during the ejection, which decelerates the spheromak. Irrespective of the bias magnetic field, an increase in the discharge current amplitude leads to an elevation in electron density and temperature. The density of the spheromak is lower than that of the jet, but the temperature is higher. This is due to the fact that the electromagnetic focusing mechanism in the jet leads to a further increase in density, while the magnetic field lines stretched during the formation of the spheromak inhibit the focusing effect and expand freely after ejection. In addition, the magnetic field stretching process consumes part of the axial kinetic energy from the plasma and converts it into magnetic energy. The subsequent magnetic reconnection event causes the magnetic energy to be dissipated resistively by heating the plasma and then be converted into thermal energy. These results give us a better understanding in the interaction between plasma and magnetic field.

show abstract

Current sheet characteristics of a parallel-plate electromagnetic plasma accelerator operated in gas-prefilled mode

Cited by 9 publications

References 39 publications

Experimental study on plasma generated by a tapered coaxial accelerator and its damage effects on a tungsten target at different angles

Experimental study on plasma generated by a tapered coaxial accelerator and its damage effects on a tungsten target at different angles

Current distribution and plasma velocity characteristics of parallel-plate accelerator under static pressure

Effects of bias magnetic field on plasma ejection and dynamic characteristics of a coaxial gun operated in gas-puffed mode

Contact Info

Product

Resources

About