An investigation was undertaken of the electrical, gasdynamic, and radiative properties of surface discharges intended as intense optical pump sources for lasers. Large‐area (≂20–300 cm2), short‐pulse (∼1 μs) planar surface discharges were produced across various ceramic and polymer substrates and operated in all of the rare gases, N2, and air at absolute pressures up to 4 atm. Parametric studies of the electrical circuitry and discharge dimensions demonstrate the importance of proper source‐driver impedance matching to short‐pulse operation and efficient electrical‐to‐optical energy conversion. Characteristic times for establishment of a conductive discharge gap in the heavy rare gases are consistent with breakdown by the single‐stroke leader mechanism. The electrical strength of the gap following discharge remains low for a time which is much greater than the current duration. The delay in recovery is believed to be controlled by continued substrate ablation occurring after the discharge rather than to ...

Electrical, gasdynamic, and radiative properties of planar surface discharges

Results of experiments with Ne, Ar and Xe as well as computer simulations are presented, aimed at testing an earlier proposed model of temporal dynamics of multichannel structure development in a pulsed high-current sliding gas discharge. The obtained and discussed experimental data include the values of an averaged channel radius, the pulsed near-surface breakdown voltage, the saturated spark resistance, the spatial structure of spark channels registered photographically under different discharge voltages and the oscilloscope traces of the discharge gap voltage. The experiments were performed at two values of gas pressure (30 and 100 kPa) with a setup in two modifications which differed from each other by an impedance (27 times) and a stored electric energy (250 times) of a pulsed power supply source. A comparison of the experimental channel structure and the discharge voltage time dependence with those calculated using the discussed model showed good agreement, and this approves an application of the model to quantitative estimations of the sliding discharge parameters. The relation revealed between the channel radii and the square root of mobility of electrons is explained by a drift of electrons in a transverse electric field. Attention is also paid to the problem of stability of a multichannel mode of the sliding discharge. Both experimental data and computer modelling demonstrate that the most stable mode of the discharge is a quasi-homogeneous one, in which the spark channels fill the interelectrode gap entirely. But a certain instability of plasma brightness seems to be an intrinsic feature of the multispark sliding discharge even in its quasi-homogeneous mode, which results from non-simultaneous initiation of the spark channels.

https://iopscience.iop.org/article/10.1088/0022-3727/40/3/015/pdf

Dynamics of multichannel and quasi-homogeneous sliding discharge formation in rare gases

An approximate model of multiple spark channel formation in a sliding gas discharge on a dielectric substrate surface is discussed. Each of the parallel sparks is treated as a constant-radius channel being quasi-static in space with a time-dependent resistance approximated by a falling function. The number of active channels as a function of discharge current is obtained empirically from the experiments being analysed. The spark model is then used for computer simulation of multiple spark formation in a conventional pulsed power supply source. The results of simulations for particular setups of earlier published works are shown to be in good agreement with the experimental data of these works.

http://iopscience.iop.org/article/10.1088/0022-3727/39/2/014/pdf

A model of multichannel mode formation in a sliding electric gas discharge

Two models of the initiation of gas discharges in a transverse discharge lamp are compared and contrasted in this paper; the volume and near-surface breakdown models. Particular consideration is given to the breakdown voltage, the breakdown formation time interval and the extent of the initial gas ionization. Experimental measurements of the breakdown parameters for Xe both in the static and in the pulsed mode of operation are given and the predictions of the two models are compared against these results. It is concluded that the near-surface gas-breakdown model is appropriate for the discharge lamps under consideration.

Transverse-discharge flashlamp operation: a surface model of gas breakdown as a first step towards representing discharge initiation

Investigation of sliding spaek in air

An investigation of a long sliding spark

A method of controlling the growth process of a sliding spark along the surface of a film dielectric by introducing emission centers from chemical compounds with a low electron work function into the surface is presented. It is shown that it is possible, by using this method, to produce a spark channel with sharp corners, such as a Z-shaped channel, and an ordered system of parallel channels, as well as a strictly rectilinear channel up to 2 m long. It is established that the rate of growth of the sliding spark is nonuniform. The mean rate is heavily dependent on the overvoltage, which is related to a reduction in the pauses in its growth.

S. I. Andreev

Papers

Investigation of sliding spaek in air

An investigation of a long sliding spark

Method of controlling the growth and formation of a system of parallel sliding spark channels in air at atmospheric pressure

Explosive emission in guided sliding discharges