scholarly journals Formation of plasma jets by a high-current discharge in metal vapor

2021 ◽  
Vol 2064 (1) ◽  
pp. 012033
Author(s):  
V A Kokshenev ◽  
N E Kurmaev
Keyword(s):  
Transmission Line ◽  
Metal Vapor ◽  
Plasma Jets ◽  
Aluminum Electrode ◽  
Marx Generator ◽  
Ceramic Surface ◽  
High Current ◽  
Plasma Sources ◽  
High Current Discharge ◽  
A Current

Abstract Plasma sources based on high-current discharges (up to 20 kA) in vapors of an aluminum electrode material with initiation over the ceramic surface are investigated. Plasma flows with a divergence angle ≤ 20° and a pulse pressure of ~ 106 Pa were obtained. A design of a crowbar spark gap based on a plasma switch with developed plasma sources built into a magnetically insulated transmission line has been proposed and tested. A crowbar mode is implemented in the transmission line with a current of a mega-ampere level with a cut-off of the load circuit from the megajoule generator GIT-12 for the period of discharge of the Marx generator.

Pulsed high-current discharge in water: adiabatic model of expanding plasma channel and acoustic wave

2021 ◽  
Author(s):  
Andrey V. Kozyrev ◽  
Andrey A. Zherlitsyn ◽  
Natalia S. Semeniuk
Keyword(s):  
Acoustic Wave ◽  
Pulsed Power ◽  
High Current ◽  
Number Density ◽  
Pulsed Discharge ◽  
Current Channel ◽  
High Current Discharge ◽  
Isothermal Plasma ◽  
A Current ◽  
Good Agreement

Abstract This paper presents the results of a theoretical and experimental study of the use of a pulsed discharge in water to obtain a strong acoustic wave in a liquid medium. A discharge with a current amplitude of 10 kA, a duration of 400 ns, and an amplitude pulsed power of 280 MW in water at atmospheric pressure created an expanding acoustic wave with an amplitude of more than 100 MPa. To describe the formation of the discharge channel, an isothermal plasma model has been developed, which made it possible to calculate both the expansion dynamics of a high-current channel and the strong acoustic wave generated by it. Our calculations show that the number density of plasma in the channel reaches 10^20 cm^(–3), while the degree of water vapour ionization is about 10%, and the channel wall extends with a velocity of 500 m/s. The calculations for the acoustic wave are in good agreement with measurements

scholarly journals Solution of Flow Problems in Unidimensional Lagrangian Hydromagnetics

1957 ◽  
Vol 10 (1) ◽  
pp. 213 ◽  
Author(s):  
RE Loughhead
Keyword(s):  
Magnetic Fields ◽  
Initial Time ◽  
High Current ◽  
Ionized Gas ◽  
Flow Problems ◽  
Solar Prominences ◽  
High Current Discharge ◽  
Infinite Extent ◽  
The Galaxy ◽  
A Current

A problem of considerable interest in many branches of astrophysics is that of the subsequent behaviour of a current which at an initial time t = 0 is largely concentrated within a given region of an ionized gas of infinite extent. In particular, it has been suggested by Alfv�n (1950) that a high current discharge in an ionized gas is likely to constrict because of the electromagnetic attraction' between parallel currents and that this constriction effect may be involved in the formation of solar prominences. Similar considerations may also be of importance in studies of magnetic fields in the spiral arms of the Galaxy.

scholarly journals X-ray and Ion Emission Sources in High-current Discharge Plasma

2015 ◽  
Vol 71 ◽  
pp. 146-149 ◽  
Author(s):  
A.V. Balovnev ◽  
E.D. Vovchenko ◽  
I.G. Grigoryeva ◽  
E.I. Dodulad ◽  
A.S. Savelov ◽  
...  
Keyword(s):  
Discharge Plasma ◽  
Emission Sources ◽  
High Current ◽  
Current Discharge ◽  
X Ray ◽  
High Current Discharge ◽  
Ion Emission

scholarly journals Post-Arc Characteristics of High-Current Arcs in Vacuum Circuit-Breakers

2019 ◽  
Vol 6 (2) ◽  
pp. 170-174
Author(s):  
N. Wenzel ◽  
W. Haas
Keyword(s):  
Short Circuit ◽  
Early Period ◽  
Metal Vapor ◽  
Transverse Magnetic ◽  
High Current ◽  
Electric Resistance ◽  
Circuit Breakers ◽  
Arc Characteristics ◽  
Current Zero ◽  
Short Circuit Currents

The post-arc (PA) characteristics of vacuum arcs in transverse magnetic field contacts are studied for short-circuit currents of up to 123 kA peak and transient recovery voltages below 875 V. The measured PA currents are interpreted in terms of an Electric Resistance Model and the models of Andrews-Varey, Langmuir-Child, and Slepian-Schmelzle. Whereas in the late PA period, the calculations do not agree well with the measurements, the PA behavior is well described in the early period after current-zero. It is concluded that the PA discharge is amplified by ionization of metal vapor particles in the boundary sheath due to electron impact.

Experimental Investigation of High-Speed/High-Voltage SMA Actuation

2017 ◽  
Author(s):  
Paul Motzki ◽  
Tom Gorges ◽  
Thomas Würtz ◽  
Stefan Seelecke
Keyword(s):  
Shape Memory ◽  
High Voltage ◽  
Supply Voltage ◽  
High Energy ◽  
Wire Diameter ◽  
High Current ◽  
Sma Actuator ◽  
The Wire ◽  
Supply Voltages ◽  
A Current

The thermal shape memory effect describes the ability of a deformed material to return to its original shape when heated. This effect is found in shape memory alloys (SMAs) such as nickel-titanium (NiTi). SMA actuator wire is known for its high energy density and allows for the construction of compact systems. An additional advantage is the so-called “self-sensing” effect, which can be used for sensor tasks within an actuator-sensor-system. In most applications, a current is used to heat the SMA wires through joule heating. Usually a current between zero and four ampere is recommended by the SMA wire manufacturers depending on the wire diameter. Therefore, supply voltage is adjusted to the SMA wire’s electrical resistance to reach the recommended current. The focus of this work is to use supply voltages of magnitudes higher than the recommended supply voltages on SMA actuator wires. This actuation method has the advantage of being able to use industry standard voltage supplies for SMA actuators. Additionally, depending on the application, faster actuation and higher strokes can be achieved. The high voltage results in a high current in the SMA wire. To prevent the wire from being destroyed by the high current, short pulses in the micro- and millisecond range are used. As part of the presented work, a test setup has been constructed to examine the effects of the crucial parameters such as supply voltage amplitude, pulse duration, wire diameter and wire pre-tension. The monitored parameters in this setup are the wire displacement, wire current and force generated by the SMA wire. All sensors in this setup and their timing is validated through several experiments. Additionally, a highspeed optical camera system is used to record qualitative videos of the SMA wire’s behavior under there extreme conditions. This optical feedback is necessary to fully understand and interpret the measured force and displacement signals.

Performance of a high‐current metal vapor vacuum arc ion source

1990 ◽  
Vol 61 (12) ◽  
pp. 3775-3782 ◽  
Author(s):  
Hiroshi Shiraishi ◽  
Ian G. Brown
Keyword(s):  
Metal Vapor ◽  
Ion Source ◽  
Vacuum Arc ◽  
High Current
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