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We have investigated the supersonic flow of dense plasma, formed by a pulsed vacuum arc, in a magnetic field of about 1 T using probe and optical diagnostics. Two separate magnetic field configurations were examined—an axial field with either converging or diverging lines of force. We find that for a low-current arc of from 0.4 to 1 kA and pulse duration of 270 $\mu \text{s}$ , the diverging magnetic field leads to increased plasma flow velocity by about a factor of 2.5, whereas the converging magnetic field reduces the velocity by about the same amount. For a high-current arc of from 5 to 30 kA and pulse duration of $40~\mu \text{s}$ , the plasma flow velocity increases, although the effect of increased field strength on flow velocity is less significant. Here, we describe these observations and other effects of magnetic field on the parameters of the vacuum arc plasma flow. [ABSTRACT FROM AUTHOR]

We have explored the generation of high-charge-state ion beams by a vacuum arc ion source. A pulsed vacuum arc with current up to several kiloamperes and pulse duration about $1~\mu \text{s}$ was used. In a vacuum arc ion source with bismuth cathode and at a background pressure of about $40~\mu $ Pa, a bismuth ion beam was formed with a maximum charge state Bi19+. For an ion accelerating voltage of 60 kV, this corresponds to a maximum bismuth ion energy of over 1 MeV. [ABSTRACT FROM AUTHOR]

We report on the generation of boron-rich plasma by a pulsed vacuum arc with lanthanum hexaboride cathode. Two different ranges of arc current pulse duration and amplitude were investigated: the first one has pulse duration of 5–20 \mu \texts and arc current of 100–700 A and the second one has pulse duration of 300 \mu \texts and arc current of 140 A. The ion mass-to-charge spectrum of the plasma was investigated by both time-of-flight spectrometry and magnetic analysis. The results of measurements of the plasma ion composition for different arc parameters are presented and discussed. For all arc parameters considered, the fractional composition of boron and lanthanum ions agrees well with the stoichiometric composition of these elements into the lanthanum hexaboride cathode. [ABSTRACT FROM PUBLISHER]

The angular distribution of the different cathode materials and gaseous ion flow from vacuum arc plasma is investigated. A metal-vapor-vacuum-arc-type ion source and a time-of-flight mass spectrometer were used. The experiments were performed using a range of different cathode materials, including C, Al, Zn, Cu, Ti, Co, Cr, W, Pb, \Cu0.7\Cr0.3, \W0.4\Co0.17\C0.43, and \Zn0.4\Pb0.6, over a range of vacuum arc discharge parameters. It was shown that, for all materials, the fraction of singly charged ions on the axis of the system is much less than that of multiply charged ions, but at the edges, the fraction of single-charged ions is greater than that of multiply charged ions; for composite cathodes consisting of light and heavy materials, there were substantially less light atoms on the axis than heavy atoms, while the opposite situation prevailed at the edges, but for cathodes with similar mass, the angular distributions of the materials were very close to each other. The velocities of ions of different materials in the composite cathode were different, but light ions had a higher velocity than those in a pure cathode plasma. With admission of gas, the angular distribution of \Ar^+ became more isotropic with increasing pressure, while the metal ion distributions changed only minimally. [ABSTRACT FROM AUTHOR]

High-charge-state heavy metal ion beams have been formed by high-power microwave heating of vacuum arc plasma confined in magnetic traps. Two types of magnetic traps were investigated: one is a simple mirror configuration, and the other is a cusp configuration with inherent “minimum-B ” structure. Pulsed high-power (>100 kW) gyrotrons with frequencies of 37.5 and 75 GHz were used for heating the vacuum arc plasma injected into the traps. Two different approaches were used for injecting the metal plasma—axial injection from a miniature arc source located on axis near the microwave window and radial injection from sources mounted radially at the midplane of the trap. High-charge-state heavy metal ion beams were extracted from the heated plasma. [ABSTRACT FROM AUTHOR]