Results 1 - 10 of 1928
Results 1 - 10 of 1928. Search took: 0.028 seconds
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[en] Amplification of XUV radiation of the 3p-3s transitions at 46.9 and 67.1 nm with a gain-length product of 2.4 and 2.6 has been observed in an argon z-pinch plasma. The amplification was demonstrated by varying the discharge length between 40 and 120 mm. A temporal resolved measurement of the gain coefficient is presented here that shows a gain of >0.15 cm-1 for a duration of more than 40 ns with a peak value of 0.2 cm-1 for the 46.9 nm line. The plasma was generated in a fast z-pinch discharge driven by a 200 kV three-stage Marx-generator. The discharge current in the alumina insulator tube with a diameter of 7 mm was 40 kA. (orig.)
[en] RFNC-VNIIEF is creating a multi-module multi-terawatt electro-physical facility "Gamma", intended for research in the field of radiation physics. Up to now RFNC-VNIIEF created the first module of the facility – a high-current pulsed electron accelerator "Gamma-1", having the following parameters: boundary energy of the electrons of ≤ 2.0 MeV, diode current of 0.75 MA, maximum electric power of 1.5 TW. Creation of the 4-module variant of the facility (Gamma-4) is the next stage of the work. This paper presents calculation research of expected characteristics of soft x-ray radiation output pulse at "Gamma-4" facility operation into a common load (Z-pinch). (author)
[en] Full text of publication follows: Distribution of matter in the discharge channel formed upon a nanosecond electrical explosion of Al wire in vacuum was studied experimentally and theoretically. Several series of experiments with 25 μm diameter 12 mm long wires were performed; the charging voltage, the current amplitude and current rise rate were U0 = 20 kV, Imax ∼ 10 kA and dI/dt = 50 A/ns, respectively . 'Shadow and Schlieren' images of the discharge channel were obtained using optical probing at the second harmonic of a YAG: Nd+3 laser (λ = 0.532 μm, τ ∼ 70 ps). Simultaneous use of optical and UV diagnostics made it possible to distinguish qualitatively different regions of the discharge channel, such as the current-carrying plasma layers and the region occupied by a weakly conducting cold matter. The simulations were performed using a program containing the Braginsky two temperature magnetic gas-dynamic model: Lagrange-Euler code RAZRYAD-2.5  on the basis of homogeneous, conservative and implicit differences of MHD schemes. Radiation energy exchange is accounted for in a multi-group (from the spectrum) approximation, using a radiation diffusion model. Heat- and electro- conductivity anisotropy in magnetic field is taken into account. Tables of thermal-physical and optical properties of aluminum were used in calculations in the present work . The influence of radiation on the distribution of the parameters of matter (temperature, density) and current density in the discharge channel was studied. Several variants with differing amounts of radiation of spectral groups were evaluated. The obtained results are compared with experimental data. This work was supported in part by the RFBR 08-08-00688, 09-02-01532, and the ESC FIAN.; . S.I. Tkachenko et. al., Plasma Physics Reports, 2009, Vol. 35, No. 9, pp. 734-753; . V.A. Gasilov et. al., Mathematical Modelling, 2003, v. 15, No 9, pp. 107-124; . A.F. Nikiforov, V.G. Novikov, V.B. Uvarov, Quantum-Statistical Models of Hot Dense Matter and Methods for Computation Opacity and Equation of State. Fismatlit, Moscow, 2000. (authors)
[en] The pinch evidence in a deuterium-filled plasma focus (PF) of only tens of joules is presented. The system operates at a very low energy in the tens of joules range (160 nF capacitor bank, 38 nH, 20-35 kV, 32-98 J, ∼150 ns current rise time), maintaining the same energy density as in large devices. The typical dip in the current derivative signal and the typical peak in the voltage signal observed in PF devices with energies of 1-1000 kJ, which are associated with pinch compression, were observed in a deuterium-filled PF operating at 50 and 67 J. The time to pinch and time to the peak current versus deuterium filled pressure were also obtained
[en] A symmetric X pinch configuration that is conducive to using large numbers of wires on ≥1 MA pulsed power generators has been tested at 1 MA. Using an initial configuration of wires before their twisting, similar to nested cylindrical wire arrays, enables a geometrically simple, compact, multilayer wire configuration at the X pinch crossing region. Multilayer X pinches with the same or different materials in the inner and outer wire layers were tested. Optimization resulted in X pinch radiation sources with peak power comparable to the most successful single layer X pinch, but with a compact, single bright X radiation source more reliably obtained using the nested configuration.