The vacuum arc cathode spot and plasma jet

Nature of high-energy ions in the cathode plasma jet of a ...

A model was developed for the plasma acceleration in a high-current (1kA) short pulsed (<1μs) vacuum arc, taking into account the high rate of rise of the spot current (dI/dt>100MA/s). A system of equations, including equations for the cathode spot and the plasma jet, was solved self-consistently with dI /dt in the range of 0.1-10GA/s.

Photographic appearance of high-current vacuum arcs prior ...

It was found that at peak current exceeding moderately the threshold value of the onset of anode spot formation, the arc is characterized by the following main features: the formation of an anode spot and an anode plasma jet occurs concurrently with a local concentration of cathode spots; the anode spot is, most often, formed on the electrode ...

Optical Investigation of the Plasma Jet of Vacuum-Arc ...

Abstract: The results of the optical study of the plasma jet of the cathode spot of a freely burning vacuum arc with copper electrodes at a current of 60 A are given, as well as of the arc stabilized with a uniform axial magnetic field of induction up to 0.18 T. The axial and radial profiles of radiation intensity for different ionization states of copper - the atom and the single and double ions - were studied.

Hydrodynamic Model of Plasma Jet of Cathode Spot of Vacuum ...

This paper concerns the paraxial structure of a plasma jet, escaping a cathode spot of a vacuum arc in the presence of an external axial magnetic field. The jet is described in the stationary single-temperature single-fluid approximation with viscosity, thermal conductivity, and radiation disregarded.

A HOT REFRACTORY ANODE VACUUM ARC IS A SOURCE

The cathode plasma jet formation and the plasma jet force are determined by the energy dissipation in the cathode body and in the cathode spot dense plasma and by returned plasma flux. The energy depends on the CPD, electron temperatures, cathode temperature, current density, and

BOUNDARY CONDITIONS FOR PLASMA JET FOOTPOINT ON

One of the property of the metal vapor arc is a plasma jet originated from the cathode spot [1] as a result of the electrode erosion. In some applications it is a shortcoming due to

Axial ion charge state distribution in the vacuum arc ...

free quasineutral plasma jet there is a small electric field of magnitude about ;100 V/m. This corresponds to a potential drop across the plasma jet of only about 10 V. In the vacuum arc plasma jet ions have a directed energy of about 50 eV,13 which is larger than the potential drop within the plasma jet.

Study of the plasma behavior produced by a vacuum arc ...

cathode-spot vacuum arc. For typical values of arc parameters, they present an analytical approximation for the ... as a principal source a single cathode spot; this produces a plasma jet of high velocity that is directed toward regions far from the cathode [11]. As the current is increased, other

On the nature of arc cathode spots in vacuum and plasmas ...

From arc tracks in vacuum it is concluded that the density of the emitted electron current is as high as 10 l2 A/m 2. It is demonstrated the spots are very non stationary with basic time constants of the order of nanoseconds, in spite of the thermal inertia of the cathode metal.

The Interelectrode Plasma SpringerLink

One section is dedicated to discuss the sources and effects of neutrals in the interelectrode plasma. Keywords ... The vacuum arc cathode spot and plasma jet, Physical model and mathematical description, Contrib. Plasma Phys. 43, 224236, (2003). ADS Google Scholar. 9.

Interelectrode plasma evolution in a hot refractory anode ...

The arc was sustained between a thermally isolated refractory anode and a water-cooled copper cathode. The arc started as a multicathode-spot (MCS) vacuum arc and then switched to the hot refractory anode vacuum arc (HRAVA) mode. In the MCS mode, the cathodic plasma jet deposits a film of the cathode material on the anode.

Study of the plasma behavior produced by a vacuum arc ...

Our results show that the cathodic arc is not directly affected by the plasma potential of the glow plasma and that the cathode material has an important influence on the plasma behavior, mainly because of the electrical and thermal conductivity of each material. Keywords: modeling; arc discharge; plasma static behavior; cathode material.

Metallic film deposition using a vacuum arc plasma source ...

The ion current fraction (ion current to the total arc current ratio) is 0.070.15 in the plasma jet generated by the cathode spots. Beilis proposed the main mechanism of cathode spot operation on different cathode metals, including plasma jet generation and expansion .

The cathode spot of a vacuum arc - IOPscience

In this review we analyze the current state of experiments and theory relating to the cathode spot of a vacuum arc. We discuss technical features of the experimental study of the near-cathode region of a vacuum arc with high time and space resolution.

Cathode spot velocity of vacuum arcs - IOPscience

Cathode spot motion in a vacuum arc with a long roof-shaped cathode under magnetic field I. I. Beilis et al 2015 Journal of Applied Physics 117 233303. Crossref. Cathode Spots Dynamic in the Initial Expansion Stage of High-Current Triggered Vacuum Arc and the Influence of Axial Magnetic Field

Vacuum Arc Ion Sources - arxiv.org

beam of an ion source. At a cathode spot the cathode material is heated, vaporized, and ionized into the plasma state. The spot has a diameter of order the of a micrometre, and the current density is extremely high, of order the of 106108 A cm2. The arc current is constricted to a small number of such spots.

Detailed Numerical Simulation of Cathode Spots in Vacuum ...

plasma (plasma generated for the arc triggering, a bulk background plasma, or a plasma cloud left over froma previous spot in the immediate vicinity); vaporization of the cathode material in the spot, its subsequent ionization and the interaction of the produced plasma

Mechanism of cathode spot splitting in vacuum arcs in an ...

A model of cathode spot splitting of a vacuum arc in an external magnetic field, which obliquely intercepts the cathode surface, was developed. The model was based on the relation between plasma kinetic pressure and the magnetic pressures produced by the self-magnetic field generated by current flow in the cathode spot and the plasma jet, and the applied external magnetic field.

Thermal spraying - Wikipedia

The plasma jet is formed by a transferred arc between a non-consumable cathode and the type of a wire. After atomization, forced air transports the stream of molten droplets onto the bore wall. The particles flatten when they impinge on the surface of the substrate, due to the high kinetic energy.

Cathodic arc deposition - Wikipedia

Cathodic arc deposition or Arc-PVD is a physical vapor deposition technique in which an electric arc is used to vaporize material from a cathode target. The vaporized material then condenses on a substrate, forming a thin film. The technique can be used to deposit metallic, ceramic, and composite films.

The hot refractory anode vacuum arc: a new plasma source ...

A new mode of the vacuum arc, the Hot Refractory Anode Vacuum Arc (HRAVA), was investigated as a plasma source for depositing coatings. Arc currents of 155340 A were sustained for periods of up to 120 s between a water-cooled Cu source cathode, and a non-consumable refractory anode, which was heated by the arc.

The vacuum arc cathode spot and plasma jet: Physical model ...

The model considers the plasma jet and the plasma generation regions, and provides electrical current continuity at the metal-plasma boundary in the cathode spot.

Optical Investigation of the Plasma Jet of Vacuum-Arc ...

The results of the optical study of the plasma jet of the cathode spot of a freely burning vacuum arc with copper electrodes at a current of 60 A are given, as well as of the arc stabilized with a uniform axial magnetic field of induction up to 0.18 T.

Nature of high-energy ions in the cathode plasma jet of a ...

The considerable increase of the energy of the ions in the cathode plasma jet with d I d t is caused by increasing of the spot plasma pressure and decreasing of the parameter e G m (e is the electron charge), which is the ion flux to the electron flux ratio. 8,14 8. I.

Vacuum Arc Discharges with Carbon Cathodes SpringerLink

I.I. Beilis, The vacuum arc cathode spot and plasma jet: physical model and mathematical description. Contrib. Plasma Phys. 43, 224236 (2003) CrossRef Google Scholar. 27. ... C. Wieckert, The expansion of the cathode spot plasma in vacuum arc discharges. Phys.

Physics of a Vacuum Arc for a Plasma Thruster Application

The cathode spot in a vacuum arc can be initiated when an adjacent to the surface primary plasma can be originated. The life time of the primary (initiating) plasma depends on the kind

The Interelectrode Plasma SpringerLink

Knowledge about the interelectrode plasma is also relevant to the application. Much of the information on arc plasmas is based on averaging over extended periods of

Sn Thin Film Deposition using a Hot Refractory Anode ...

The conventional vacuum arc plasma jet is also used for depositing coatings [4] which is related to the physical vapor deposition (PVD) techniques. The main problem with it is the generation of macroparticles (MPs) at the cathode. The Hot Refractory Anode Vacuum Arc (HRAVA) was proposed in last decade as a thin film deposition

ARCS AND SPARKS PHOTO GALLERY - Electrical Discharge and ...

The most frequently encountered vacuum arc mode, the cathode spot or cathodic arc, the plasma is produced by one or more minute, highly luminous areas on the cathode surface, known as cathode spots. Each cathode spot emits a plasma jet of highly ionized metal vapor, typically with velocities of 10 km/s.

Properties of Arc Cathode Spots - hal.archives-ouvertes.fr

Properties of Arc Cathode Spots B. Jiittner Humboldt-Universitat zu Berlin and Max-Planck-Institute for Plasma Physics, Mohrenstrasse 41, 1011 7 Berlin, Germany Abstract. Arc cathode spots operating by formation of surface-microplasmas are reviewed for discharges in vacuum and in gases.


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