A Technique for Measurements of Energy Release in Pulsed Gas Discharge in Short Interelectrode Gaps

Abstract

A technique based on measurement of the active voltage in a low-inductance section of a discharge circuit with two interelectrode gaps in a three-gap gas discharge generator of aerosol is developed for use in determining energy release in a pulsed gas discharge in short interelectrode gaps. It is shown that the effi ciency of energy release increases as the number of serially connected electrodes is increased. Keywords: pulsed gas discharge, energy release, short interelectrode gas, cathode potential drop.The widespread use of the phenomenon of pulsed gas discharge requires a determination and optimization of the released energy. This is especially crucial when creating light-emitting devices, equipment for electro-erosion treatment, switches of high electrical power, and charged particle accelerators in which energy consumption is one of the basic characteristics of the entire device. The class of electrophysical devices with pulsed gas discharge includes high-pressure fl ash lamps, different types of high-current accelerators of electrons and ions with plasma cathodes, pulsed plasma generators, gas-discharge switches, electrical spark alloying devices, sparks of fuel ignition systems and gas-discharge generators of nanodimensional aerosols [1][2][3].In pulsed gas-discharge generators of aerosols, fl uxes of nanoparticles are formed by electrical erosion of the electrodes of a discharge gap accompanied by the formation of vapor-droplet dispersion and subsequent condensation in a process of rapid cooling. In such devices, a portion of the energy released in a narrow cathode layer (10 −2 mm) characterized by a drop in potential is expended on the generation of nanoparticles, while the energy of the plasma column of the pulsed discharge is consumed basically in heating and radiation. To minimize purposeless utilization of the energy released in an interelectrode gap, therefore, the distance between the electrodes is selected in the range 0.5-2 mm. In such devices, the large pulse current created by the discharge of a reservoir capacitor has the form of damped vibrations, since as a rule the critical resistance of the circuit signifi cantly exceeds the equivalent resistance. The following question is very critical: what fraction of the released electrical energy is consumed directly in the transformation of the material of the electrode from the solid phase into nanoparticles. In order to obtain such data, a technique is needed for measurements of energy release in a pulsed gas discharge in a small interelectrode gap. The technique must include an algorithm for generating primary data on the pulse current through a discharge gap and the active drop in potential in the gap as a function of time. The Joule integral of energy release is calculated on the basis of the obtained results. Such a problem has been successfully solved for short discharge gaps with stationary arc where reliable measurement of the pulse voltage between the electrodes represents a special diffi culty [4].

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