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Using the example of an electron source with a plasma cathode based on a low-pressure arc discharge with grid stabilization of the cathode/emission plasma boundary and an open anode/beam plasma boundary, a mechanism is described for increasing the electrical strength of a high-voltage accelerating gap by introducing a series negative current feedback (NCF) in the accelerating interval, which makes it possible to level out uncontrolled bursts of the beam current during its pulse. The introduction of NCF is achieved by using a special electrode in the space of the plasma emitter connected through a resistance to the anode of the arc discharge, and the main task of which is to intercept accelerated ions penetrating into the emitter from the high-voltage accelerating gap, due to which the current of electron emission from the arc discharge plasma decreases by a value proportional to the ion current in the accelerating gap. Since most sources and accelerators of electrons with plasma cathodes based on discharges of various types have a similar principle of operation, the use of this method will not only expand the limiting parameters of the generated electron beams, but also increase the stability of the operation of such electron sources, and, accordingly, beam irradiation of various materials and products. [ABSTRACT FROM AUTHOR]

This work is a continuation of study [1] devoted to the effect of a submillisecond pulsed electron beam on the surface of hypereutectic silumin (AlSi20). Experiments are performed using a SOLO electron source with a plasma cathode in which the generated pulse power can be controllably changed during the pulse, which allows control of the energy-input rate to the target surface. The application of such a unique electron source enables consideration of the effect of maintaining the surface temperature of the irradiated sample (at a level close to the silumin melting point) at a pulse duration of less than 1 ms on modification of the properties of this surface. An increase in the time of maintaining the sample-surface temperature is shown to improve its microhardness and wear resistance. The modified layer has a cell structure similar to that formed during high-speed crystallization. The modified-layer depth reaches 60 μm. [ABSTRACT FROM AUTHOR]

The article presents results of studying the dynamics of a submillisecond low-pressure arc discharge in an electron source with a grid plasma emitter and a plasma anode, as well as the formation of an electron beam generated by it in a guiding magnetic field. Measurements of the currents to the electrodes of the plasma emitter discharge system and to additional probes installed in it demonstrated the spatial rearrangement of the discharge with subsequent achievement of a quasi-steady shape of the current density distribution on the emission electrode. Analysis of the current oscillograms at the end of the discharge current pulse made it possible to estimate the contribution of the electron emission current from the plasma emitter to the total current in the accelerating gap in the mode when the measured beam current is equal to or exceeds the discharge current. The factors responsible for reducing the spatial inhomogeneity of the beam current density are determined, and recommendations are given for improving its uniformity. [ABSTRACT FROM AUTHOR]

We describe a method for dynamic power control of a submillisecond pulsed electron beam in a "SOLO" type source with plasma cathode. The beam power is controlled by dynamic variation of the beam current amplitude with the corresponding low-inertia change in the concentration of emissive plasma. This method can be used to generate submillisecond electron beams of variable power (up to 10 MW at a maximum variation rate not exceeding 0.5 W/μs)—in particular, for the processing of various metallic materials with modification of their functional properties by controlled beam energy supply to the material surface. [ABSTRACT FROM AUTHOR]