On the formation of a barrier discharge in excilamps

The dynamics of discharge formation in a two-barrier XeBr excilamp is studied. It is found that the maximal voltage drop across the lamp and the breakdown voltage of the discharge gap vary with time nonmonotonically upon switching on. This indicates that the discharge goes through several stages before it reaches the steady state. An increase in the lamp capacitance prior to secondary breakdown at the contracted stage of the discharge suggests the formation of a region with a high residual conductivity in the gas-discharge space after primary discharge. It is shown that the use of a keep-alive discharge prevents the arc stage when the excilamp is switched on.     

Determination of the electron concentration and temperature,as well as the reduced electric field strength,in the plasma of a high-voltage nanosecond discharge initiated in atmospheric-pressure nitrogen by a runaway electron beam

We report on the results of spectroscopic measurements of electron concentration N _e and temperature T _e , as well as the reduced electric field strength E/N in the plasma of a high-voltage nanosecond discharge in the gap with a strongly nonuniform electric field distribution, which is filled with nitrogen under the atmospheric pressure. The possibility of using the method for determining T _e and E/N, which is based on the determination of the ratio of the peak intensities of the ionic N ₂ ⁺ (λ = 391.4 nm) and molecular N₂ (λ = 394 nm) nitrogen bands, is proved. We detected the mean values of quantities N _e , T _e , and E/N amounting to ～2 × 10¹⁴ cm^?3, ～2 eV, and ～240 Td, respectively. In addition, the dynamics of these quantities is determined.     

Transition of a diffuse discharge to a spark at nanosecond breakdown of high-pressure nitrogen and air in a nonuniform electric field

The transition of a runaway-electron-induced diffuse discharge initiated in a nonuniform electric field under a high pressure of air and nitrogen to a spark is studied. High-voltage pulses with a rise time of 0.5 ns are applied to a discharge gap with a tubular cathode having a small radius of curvature. It is shown that the leader of the spark discharge propagates toward the tubular cathode along preproduced tracks and may pass from one track to another. For a pulse rise time of about 0.5 ns and a gap length of 12 mm or more, it is found that spark leaders originating at the cathode (which has a small radius of curvature) do not reach the anode and accordingly, do not cause the spark breakdown of the gap. It is confirmed that the spark breakdown of the gap is associated with a spark leader that moves away from the plane electrode after the appearance of a bright spot on it.     

Parameters of the beam plasma formed by a forevacuum plasma source of a ribbon beam in zero-field transportation system

We have studied the generation of the beam plasma formed by a forevacuum plasma source of a ribbon electron beam in the conditions of its transportation without an accompanying magnetic field. The ignition conditions in the beam transportation region of the beam–plasma discharge producing a plasma formation of the plasma sheet type with a plasma concentration of ~10¹⁶ m^–3 and an electron temperature of 1–2.5 eV have been determined. The attained values of parameters and the sizes of the plasma formation make it possible to use it in technologies of the surface modification of planar extended articles.     

Emission characteristics of a pulsed discharge in xenon

Emission characteristics of a high-current pulsed discharge in xenon are studied experimentally. The study is aimed at developing a source of spontaneous UV radiation (with λ ≤ 250 nm) for controlling highvoltage crystalline diamond switches.     

On the Influence of Electron Energy on Characteristics of the Cherenkov Radiation and Cathodoluminescence

Russian Physics Journal - A review of the results of investigations of the Cherenkov radiation (CR) and pulsed cathodoluminescence during irradiation of different crystals and...     

Generation regimes for the runaway-electron beam in gas

The generation of the runaway-electron beam in nitrogen and helium is studied at an oscillator voltage of about 25 kV. Various regimes of the electron beam generation with a pulse duration ranging from 200 ps to several nanoseconds are realized depending on the pressure in the gas diode. An ultrashort avalanche electron beam (UAEB) with a low (10–20%) variation in the voltage across the gap is obtained at a relatively high pressure in the gas diode. The UAEB generation can be delayed relative to the leading edge of the voltage pulse by tens of nanoseconds at low oscillator voltages.     

Excess-energy electrons in a nanosecond electron beam from a vacuum diode

The characteristics of an IMA3-150É sealed-off vacuum diode connected to a RADAN-220 nanosecond pulser are investigated. It is found that the electron beam behind the foil contains electrons with an energy exceeding the voltage applied to the diode. It is shown that the elevated-energy electrons appear at the leading edge of a current pulse, the FWHM of the current pulse of these electrons is 200–450 ps, and the pulse amplitude reaches several tens of amperes.