[en] This work deals with an analysis of cumulative effects in Plasma Focus discharges resulting in plasma jet generation. Experimental results of studies of the plasma jet interaction with different targets are presented. New opportunities to produce soft X-ray (SXR) radiation are discussed. (author)

[en] One of the directions under development now at RRC Kurchatov Institute is the study an opportunity to use Plasma Focus-type facilities as drivers for the magnetic compression of liners. The main goal of the study is to produce experimental data on the compression of foam loads at PF-3 facility. A loading device, allowing one to install the liner at the preset position in the discharge volume without violation of the vacuum conditions, has been developed for improving the current sheath parameters. The experiments with thin-walled agar foam liners with linear mass 0.3 - 4.0 mg/cm at discharge current 2 - 3 MA are performed. Main outcome of these experiments is demonstrating of effect of easy 0.3 - 0.6 mg/cm liners compression with velocity ∼3 x 10⁶ cm/s. (author)

[en] Studies of the plasma focus as a driver for magnetic compression of liners are going on. As a result of the discharge system modernization, the value of the discharge current has been increased up to 4 MA in its maximum and up to 3 MA in the stage of pinch formation. A number of experiments are achieved with foam and wire loads at the enhanced discharge current. A two-fold increase of the velocity of easy loads compression (up to ∼(6-7)x10⁶ cm/s) is obtained

[en] The study is devoted to the investigation of plasma focus systems as a driver for magnetic compression of liners. The experiments on the comparative analyse of the foam and multiwired liners compression were done on the Filipov-type plasma focus facility PF-3. The compression of the light (linear mass 0.3 - 0.6 mg/cm) liners with velocity (2-3) centre dot 10⁶ cm/s was obtained. It is shown that under conditions of considerable radiation fluxes at the usage of strongly-radiating working gases a preliminary heating of the target can be attained. This results in acceleration of the transition of initially - condensed substance into plasma state, that assists in overcoming 'cool start' problem

[en] The new approaches developed recently in the plasma focus (PF) system studies make the efforts in the PF-optimization, as a current generator, and in the transportation of a current to the axis zone to be urgent. The PF-3-facility design description in detail and its main electrical engineering characteristics are given first in the paper, as well as the results of studying the dynamics of a plasma current sheath by optical techniques (electron-optical converters, streak-camera). Some techniques of the liner loading deliveries into the current sheath compression zone, providing an opportunity for the multiple replacement of multiwire liners without violation of vacuum conditions, are discussed and the diagnostics set of the PF-3-facility is described. The realized PF-3-facility modernization allows one to perform the experiments with multiwire and other liners at the discharge current amplitude of 3 = 5 MA. (author)

[en] The main content of the studies on PF-3-facility was the experiments with various mediums as a plasma source. The facility studies as the driver for magnetic compression of liners are going on. Experiments with wire arrays have been achieved at filling discharge chamber with deuterium under the pressure 3-4 Torr. Compression dependence on wires number was investigated. The better result was achieved with liner made of 60 tungsten wires, 6 μm in diameter (linear mass 0.33 mg/cm). Liner compression is accompanied by the pulse of X-ray radiation. In case of 40 wires of same diameter, despite of smaller linear mass, compression is characterized by enough long-lived (∼ 300 ns) stage, during which the wires remain fixed after contact with the current sheath. Practically it was not observed the liner compression in case of 24 wires. In cooperation with Czech Technical University experiments with CD₂ fiber located on the discharge system axis were done. Fiber pre-heating by the radiation of the collapsing current sheath was confirmed in experiments with neon as a working gas: initial fiber diameter increasing in 2-3 times was observed on the shadow pictures. However, neutron radiation was not observed in these shots. At the same time the neutron output at level ∼ 5 · 10⁶ neutron/shot ±50% was confidently registered in the shots with argon. The neutron radiation output depends on symmetry of the plasma sheath convergence to the fiber. The studies of the dense high-temperature plasma interaction with the condensed dispersion mediums (dust) are going on. The different modifications of the dust source were tested and dust target parameters were determined with the special testing stand at the conditions maximally closed to the conditions of real experiments. The experiments have shown the possibility of the effective control on the final discharge stage. Pinch dynamics dependence on dust target parameters was explored. The modes with enhanced MHD-stability are found in the shots with neon and dust fraction of fine-disperse (2-10 μm) Al₂O₃ powder. (author)

No abstract available

[en] The results of experimental studies are given for the process of micropinch structure formation in Mather-type plasma focus (PF) discharges with Ar or Xe additions in deuterium. A modelling analysis is done on the influence of heavy impurity line radiations on the evolution dynamics for m = 0 instabilities. A comparative analysis of PF devices of Mather and Filippov geometries is carried out over a wide range of energies. It is shown that in a PF device magnetized ion-plasma interactions accompanied by plasma heating occur. This fact explains the well known scaling laws. Methods of increasing plasma temperature and density in PF devices are indicated. (author). 6 refs, 3 figs

[en] In order to gain an insight into generation mechanisms for electron beams (EB) in Plasma Focus (PF) the time-evolution of their energy spectra should be well understood. Information of this evolution may be obtained in studies on hard X-ray (HXR) appearing in EB interactions with solid targets. In its general form, this problem is fairly complicated, requiring a great number of multi-parameter time-measurements of HXR spectra and thorough knowledge of the geometry. In the present paper, a method is used which can provide quantitative estimations of temporal courses of the energy and the current of the main EB fraction. The method is based on comparisons between the signals of a pair of identical detectors recording HXR, one of the detectors being covered with an absorbing filter. (author) 5 refs., 3 figs

[en] Toroidal plasmoids in the neck of a pinching plasma column in the plasma focus, vacuum spark and fast Z-pinch, can be treated as Kvartskhava structures. Computer simulations of such plasmoids were carried out. Tangential discontinuities in pinching plasmas are also discussed. (author)