scholarly journals The Electrodynamic Mechanism of Collisionless Multicomponent Plasma Expansion in Vacuum Discharges: From Estimates to Kinetic Theory

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7608
Author(s):  
Vasily Kozhevnikov ◽  
Andrey Kozyrev ◽  
Aleksandr Kokovin ◽  
Natalia Semeniuk
Keyword(s):  
Plasma Expansion ◽  
Vacuum Discharge ◽  
Interelectrode Space ◽  
Cathode Plasma ◽  
Multicomponent Plasma ◽  
Non Thermal Plasma ◽  
Charged Ions ◽  
Discharge Gap ◽  
Positive Ion ◽  
A Current

This paper is devoted to the study of collisionless multicomponent plasma expansion in vacuum discharges. Based on the fundamental principles of physical kinetics formulated for vacuum discharge plasma, an answer is given to the following question: What is the main mechanism of cathode plasma transport from cathode to anode, which ensures non-thermal metallic positive ion movement? Theoretical modeling is provided based on the Vlasov–Poisson system of equations for a current flow in a planar vacuum discharge gap. It was shown that the non-thermal plasma expansion is of a purely electrodynamic nature, caused by the formation of a “potential hump” in the interelectrode space and its subsequent movement under certain conditions consistent with plasma electrodynamic transportation. The presented results reveal two cases of the described phenomenon: (1) the dynamics of single-component cathode plasma and (2) multicomponent plasma (consisting of multiple charged ions) expansion.

scholarly journals Scaling of DD fusion power in a nanosecond vacuum discharge

2021 ◽  
pp. 16-24
Author(s):  
Yurii Kurilenkov ◽  
Vladimir Tarakanov ◽  
Aleksandr Oginov
Keyword(s):  
Virtual Cathode ◽  
Vacuum Discharge ◽  
Interelectrode Space ◽  
Fusion Power ◽  
Partial Penetration ◽  
Hollow Anode ◽  
Initial Stage ◽  
A Current

Earlier, in a nanosecond vacuum discharge (NVD) with a deuterated Pd anode, the appearance of DD neutrons was observed not only at the well-studied quasi-stationary stage, where a virtual cathode (VC) appears in the interelectrode space, but also at the very initial stage of the discharge. An analysis of the experiment shows that the autoelectron beam can play the role of a kind of trigger for starting DD syntheses processes on the surface or in the bulk of the Pd anode, but its mechanism at the initial stage of the discharge remained unclear. In this work, we performed PiC modeling of the possible partial penetration of a beam of autoelectrons into hollow anode Pd tubes. This leads to the formation of very small short-lived VCs inside individual Pd tubes, where, starting from a current of 100 A, DD microsynthesis is possible. It is shown that in devices with oscillating ions the favorable scaling of the DD fusion power, which increases with decreasing VC radius, can be retained up to rVC  0.02 cm.

scholarly journals Time evolution of the two-dimensional expansion velocity distributions of the cathode plasma in pulsed high-power diodes

2013 ◽  
Vol 31 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Jie Yang ◽  
Ting Shu ◽  
Yuwei Fan
Keyword(s):  
High Power ◽  
Cathode Surface ◽  
Transverse Velocity ◽  
Longitudinal Velocity ◽  
Expansion Velocity ◽  
Two Dimensional ◽  
Plasma Expansion ◽  
Cathode Plasma ◽  
Power Diodes ◽  
Diode Current

AbstractA combination of electrical and optical diagnostics has been used to investigate the time evolution of the two-dimensional expansion velocity distributions of the cathode plasma in pulsed high-power diodes. The perveance model based on the Child-Langmuir law was used to calculate the expansion velocity of the diode plasmas from voltage and current profiles. Additionally, a four-channel high speed framing camera was used to observe the formation and subsequent movement of the cathode plasma. More accurate and valuable information about the dynamics of the cathode plasma was also acquired by utilizing the digital image processing methods. Results from the experiments and theoretical analysis were compared. In this paper, the experiments have been performed using a high-voltage pulse generator with 200 kV output voltage and 110 ns pulse duration. Current densities up to 440 A/cm2were produced. The observation of the cathode plasma expansion in transverse direction indicated that the diode current was cathode-limited in the current rising stage (the first 60 ns of the current pulse). The perveance model should be modified taking in account the time dependent expanding plasma surface (i.e., not the whole cathode surface) for this period. The velocity in the direction parallel to the cathode surface (transverse velocity) was much larger than that in the direction perpendicular to the cathode surface (longitudinal velocity), and further, it dropped from 90 cm/μs to nearly 20 cm/μs rapidly. It was shown that, during the current flattop stage, the plasma filled out all the surface of cathode and the diode current was space-charge-limited. The values of the transverse velocity and longitudinal velocity were nearly the same and decreased relatively slowly. The satisfactory coincidence of experimental and calculated (both were in the range of 6–8 cm/μs) values of the cathode plasma expansion velocities was obtained.

Influence of the laser plasma-expansion specific on a cathode jet formation and the current stability in a laser-ignited vacuum discharge

2018 ◽  
Vol 25 (8) ◽  
pp. 083107 ◽  
Author(s):  
I. V. Romanov ◽  
I. P. Tsygvintsev ◽  
V. L. Paperny ◽  
A. A. Kologrivov ◽  
Yu. V. Korobkin ◽  
...  
Keyword(s):  
Laser Plasma ◽  
Plasma Expansion ◽  
Vacuum Discharge ◽  
Jet Formation

OPTIMIZATION OF NON THERMAL PLASMA REACTOR PERFORMANCE FOR THE DECOMPOSITION OF XYLENE

2016 ◽  
Vol 78 (8) ◽  
Author(s):  
Nor Faraliana Shazwani Nor Azmi ◽  
Abdullahi Mohammed Evuti ◽  
Mohd Ariffin Abu Hassan ◽  
R. K. Raja Ibrahim
Keyword(s):  
Flow Rate ◽  
Thermal Plasma ◽  
Applied Voltage ◽  
Gas Flow ◽  
Plasma Reactor ◽  
Gas Flow Rate ◽  
Reactor Performance ◽  
Model Predictions ◽  
Non Thermal Plasma ◽  
Discharge Gap

Non Thermal Plasma (NTP) is an emerging method used for the decomposition of volatile organic compounds (VOCs). This research focuses on the optimization of NTP reactor performance for decomposition of xylene from wastewater using response surface methodology (RSM) by operating the NTP reactor at applied voltage of 12-15 kV, discharge gap of 2.0-3.0 cm and gas flow rate of 2.0-5.0 L/min. An optimum xylene removal efficiency of 81.98% was obtained at applied voltage 15kV, discharge gap 2.09cm and gas flow rate at 2.36 L/min. The experimental removal efficiencies and model predictions were in close agreement with an error of 0.63%. 

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