Calculation of the Inductance of Plasma Column at PF-1000 Device with Assumed Current Distribution

Processed data is taken from the D-D fusion reaction experiments on PF-1000 at IFPILM Warsaw, operating with 2 MA, 1011 neutron yield, using interferometry, temporal resolved neutron diagnostics, magnetic probe diagnostics and X-ray diagnostics. The inductance is calculated under two different circumstances: with the known distribution function determined by the magnetic probe signal, and with the border of the plasma column determined from interferograms using Matlab. The inductance of the whole column is calculated using the formula for the inductance of a coaxial cylinder

Calculation of the Inductance of Plasma Column at PF-1000 Device with Assumed Current Distribution

Processed data is taken from the D-D fusion reaction experiments on PF-1000 at IFPILM Warsaw, operating with 2 MA, 1011 neutron yield, using interferometry, temporal resolved neutron diagnostics, magnetic probe diagnostics and X-ray diagnostics. The inductance is calculated under two different circumstances: with the known distribution function determined by the magnetic probe signal, and with the border of the plasma column determined from interferograms using Matlab. The inductance of the whole column is calculated using the formula for the inductance of a coaxial cylinder

Vyzkumne centrum laseroveho plazmatu na FEL CVUT 2001.

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Experiments and simulations on the possibility of radiative contraction/collapse in the PF-1000 plasma focus

Experimental studies of discharges in the plasma focus facility with neon filling and respective numerical simulations employing the radiative Lee code are reported. The pinch currents exceed the Pease-Braginskii current, which indicates that radiative losses are larger than heating and that contraction of the formed plasma should occur. Both of these effects were indeed observed. Parallel numerical simulations were crucial for the identification of such an effect

Evolution of the small ball-like structures in the plasma focus discharge

The experiments were carried out in the PF-1000 plasma-focus device at the maximum current reaching about 2 MA, at the deuterium or neon filling and with deuterium injected from a gas-puff nozzle placed on the axis of the anode face. Ball-like structures of diameters of 1-12 mm were identified in interferometric and XUV pinhole camera frames. We made the statistical description of their parameters. A lifetime of the ball-like structures was in the range from 30 to 210 ns, and in some cases even more. These structures appeared mostly at the surface of the imploding plasma shell and they did not change their position in relation to the anode end. During the evolution of these structures, interferometric fringes were observed near the surfaces of the structures only, and their internal parts were initially chaotic (without noticeable) fringes. Subsequently the number of interferometric fringes increased (the internal ‘chaotic’ area was filled with fringes too) and later on it decreased. The radii of the ball-like structures were mostly increasing during their existence. The maximum electron density reached the value of 1024 to 1025 m-3. The ball-like structures decayed by absorption inside the expanded pinch column and/or gradually expired in rare plasma outside of the dense plasma column

Conditions for radiative cooling and collapse in the plasma focus illustrated with numerical experiments on PF1000

Reduced Pease-Braginskii currents are estimated for a linear pinch in a range of gases, namely, D, He, Ne, Ar, Kr, and Xe. A characteristic depletion time is defined as the time it takes for the plasma focus (PF) pinch energy to be radiated away. This quantity is used as an indicator for expectation of radiative collapse. The depletion times in various gases are estimated in units of pinch duration. The values indicate that in D and He, the radiation powers are small, resulting in such long depletion times that no radiative collapse may be expected in the lifetime of the focus pinch. In Ne, low tens of percent are radiated and significant cooling and reduction in radius ratio may be anticipated. In Ar, Kr, and Xe, the depletion time is only a fraction of the estimated pinch duration, so radiative collapse may be expected. Numerical experiments are then carried out with a circuit-coupled code, which incorporates radiation-coupled dynamics with PF pinch elongation and plasma self-absorption. The latter eventually limits the radiated power and stops the radiative collapse. These results show the detailed dynamics and confirm the expectations arising from depletion times discussed above

Generation of Secondary Particles from Subnanosecond Laser Irradiation of Targets at Intensities of 10^16 W/cm^-2

none15J.Krasa; D.Margarone; D.Klir; A.Velyhan; A.Picciotto; E.Krousky; K.Jungwirth; J. Skala; M.Pfeifer; J. Ullschmied; J.Kravarik; K.Rezac; P.Kubes; P.Parys; and L.RycJ., Krasa; D., Margarone; D., Klir; A., Velyhan; Picciotto, Antonino; E., Krousky; K., Jungwirth; J., Skala; M., Pfeifer; J., Ullschmied; J., Kravarik; K., Rezac; P., Kubes; P., Parys; L., Ry