Peaking the current of a microsecond generator operating into a plasma load

A configuration of a plasma flow switch intended for peaking the current of a capacitor bank operating into a liner load has been proposed and tested where the current bridge and the liner are formed with the help of a single pulsed gas valve. The design of the load unit has been optimized for the efficiency of the energy transfer from the energy store to the liner. The peaker was tested in experiments on generation of soft x-radiation and K-radiation of neon. High efficiency of conversion of the magnetic energy of the primary store to x-radiation has been demonstrated. Institute of High Current Electronics, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 36–40, December, 1999.     

On the Size of the Soft X-Ray Radiation Source Based on an X-Pinch

Russian Physics Journal - The advent of X-pinch based compact radiographs has significantly expanded the application field of pulsed radiography for diagnostics of fast processes. The key point...     

Optical Recording of the Surface Plasma of Cylindrical Conductors in Strong Magnetic Fields

Russian Physics Journal - Results are presented of experiments on the explosion of aluminum and titanium conductors that were carried out on a multipurpose impulse generator (MIG) (current...     

Investigation of the toxicity of aqueous media after high-energy exposure by the spectralluminescent methods

The spectral and luminescent characteristics of aqueous solutions in the presence of phenol and natural organic acids are investigated after high-energy exposure (to a diffuse barrier discharge or an electron beam) in comparison with conventional ozonization. The toxicity of solutions is determined by the bioluminescent methods. It is demonstrated that the pulsed diffuse barrier discharge causes efficient transformation of phenol (C = 10^–3 M) in water. After such exposure, the solutions possess extreme toxicity. Addition of humic acids to the aqueous phenol solution results in decreased rates of phenol transformation and reduces the degree of toxicity after the high-energy exposure.     

Compact X-ray radiograph based on a plasma gun

The results of the experiments on the formation of a plasma emitter with small spatial dimensions for pulsed radiography in the soft X-ray spectral range are presented. Emitting hot plasma was formed as a result of compression of the plasma jet by a current pulse with amplitude I _m = 215 kA and rise time T _fr = 200 ns. For the jet formation, we used a plasma gun based on the arc discharge (I _m = 8.5 kA and T _fr = 6 μs) initiated by breakdown over the surface of a dielectric in vacuum. The experiments were carried out with aluminum, tin, copper, and iron plasma jets. A single emitter, i.e., point Z-pinch (PZ-pinch), was formed when an interelectrode gap of a high current generator of 1.3–1.5 mm was used. The smallest spatial dimensions of the emitting region were obtained with the use of aluminum and tin. For a tin jet, the diameter of the emitting region was 7 ± 2 μm and its height was 17 ± 2 μm. The emission pulse duration at half-height was 2–3 ns. The total emission yield per pulse in the spectral range 1.56–1.90 keV was 30–50 mJ for the aluminum pinch and 10–30 mJ for the tin pinch. The developed method makes it possible to carry out radiographic examination of microobjects (including biological ones) 1–1000 μm in thickness, with spatial (10–20 μm) and time (2–3 ns) resolution.     

The Electric Explosion of Conductors in Megagauss Magnetic Fields

The results are presented from an experimental study of the explosion of copper conductors performed at ~2 MA current pulse with a rise time of 100 ns using the MIG generator. Using a HSFC Pro optical camera, large-scale instabilities with wavelengths of 0.2–0.5 mm are recorded on the surface of the conductor. The instabilities are tongue-shaped ejections of plasma expanding at the speed of sound in the direction opposite the gradient of the magnetic field. The obtained data are analyzed using two-dimensional magnetohydrodynamic simulation. It is shown the emergence of the observed structure was likely due to the growth of flute instabilities.     

Metastable Fluid Decay During Electric Explosion of Metallic Foils

Russian Physics Journal - Results of experimental investigations into overheated metastable fluid decay during electric explosion of metallic foils are presented. Experiments have been performed...     

Small-Size High-Current Generators for X-Ray Backlighting

Russian Physics Journal - The paper deals with the soft X-ray backlighting based on the X-pinch as a powerful tool for physical studies of fast processes. Proposed are the unique small-size pulsed...     

Metastable states and their disintegration at pulse liquid heating and electrical explosion of conductors

The regularities of formation of metastable states and their disintegration under pulse liquid heating and electrical heating and explosion of conductors are studied. With a high energy flux density, the phase transitions occur with a high intensity of heat and mass fluxes, leading to spontaneous generation of a new phase and to phase explosion. The basic features of bubble-like disintegration in not uniformly superheated water and alcohol layers on the microheater are found. Regularities of matter disintegration with electrically exploded conductors are obtained. The metastable liquid disintegration is experimentally investigated for characteristic times of matter transfer to a metastable state of 1 to 4 μs; phase transitions during electric conductor explosion are studied at characteristic times of transfer to a metastable state to 200 ns. A common approach to describing the effects with radically different characteristic times of transfer of the matter to a metastable state is developed.     

Formation of tight plasma pinches and generation of high-power soft x-ray radiation pulses in fast Z-pinch implosions

Argon K-shell plasma radiation source experiments were carried out on the GIT-12 generator [Bugaev, S.P. et al., 1997, Russian Phys. Journal, 40, 38] for a long (300 ns) implosion regime. The performance of a shell-on-solid-fill double gas puff was characterized in the experiments with and without an external axial magnetic field. The maximum Ar K-shell radiation yield registered in the experiments without an axial magnetic field was at the level of 1100 J/cm. This yield is consistent with the theoretically predicted yield for a short (100 ns) implosion regime. The experiments showed that the initial magnetic field which provides stabilization of the shell-on-solid-fill double gas puff was lower than that required for stabilization of a single annular gas puff. Satisfactory stabilization of the double gas puff was observed at an initial axial magnetic field of 1.4 kG. The maximum Ar K-shell radiation yield registered in the experiments with the axial magnetic field did not exceed 400 J/cm. A sharp reduction of the K-shell yield cannot be explained only by taking into account the energy losses associated with the compression of the axial magnetic field. Original Text ? Astro, Ltd., 2006.