The Z accelerator [R. B. Spielman, W. A. Stygar, J. F. Seamen et al., Proceedings of the 11th International Pulsed Power Conference, Baltimore, MD, 1997, edited by G. Cooperstein and I. Vitkovitsky (IEEE, Piscataway, NJ, 1997), Vol. 1, p. 709] at Sandia National Laboratories delivers ∼20MA load currents to create high magnetic fields (>1000T) and high pressures (megabar to gigabar). In a z-pinch configuration, the magnetic pressure (the Lorentz force) supersonically implodes a plasma created from a cylindrical wire array, which at stagnation typically generates a plasma with energy densities of about 10MJ∕cm3 and temperatures >1keV at 0.1% of solid density. These plasmas produce x-ray energies approaching 2MJ at powers >200TW for inertial confinement fusion (ICF) and high energy density physics (HEDP) experiments. In an alternative configuration, the large magnetic pressure directly drives isentropic compression experiments to pressures >3Mbar and accelerates flyer plates to >30km∕s for equation of state ...

Pulsed-Power-Driven High Energy Density Physics and Inertial Confinement Fusion Research

High inductive helical support provides a solution to controlling the alignment error of inner electrodes in magnetically insulated transmission lines (MITLs). Three-dimensional particle-in-cell simulations were performed to examine the current loss mechanism and the effects of structural parameters on electron flow in an MITL with a helical inductor. An empirical expression related to the ratio of electron current loss to anode current and the ratio of anode current to self-limited current was obtained. Electron current loss caused by helical inductor with different structures was displayed. The results indicate that the current loss in an MITL, near an inductive helical support, comprises both the inductor current and the electron current loss. The non-uniform structure and current of a helical inductor cause an abrupt change in the magnetic field near the helical support, which leads to anomalous behavior and current loss of electron flow. In addition, current loss in the inductive helical-supported MITL is negligible when the inductance of the support is sufficiently high. This work facilitates the estimation of electron current loss caused by the inductive helical support in MITLs.

Particle-in-cell simulations of current loss in magnetically insulated transmission line with inductive helical support

In this work, a circuit-PIC coupled model for 3D simulation is developed, which can be used in pulsed power system with magnetically insulated transmission lines (MITLs). The circuit-PIC coupled algorithm consists of an external circuit algorithm and an algorithm which counts the jounced interface of the circuit and the grids for PIC simulation. The circuit-PIC coupled model has been demonstrated and implemented in a 3-D conformal finite-difference time-domain PIC code, UNIPIC. In this paper, the coupled model of 3D simulation is applied in a coaxial MITL system with a helical supporter, and this MITL is driven by Marx Generator. This work provides an approach to simulating MITL system which is azimuthal asymmetry in the power flow or structure.

Luo Wei

Papers

Circuit-PIC coupled model of 3D simulation for magnetically insulated transmission line system