CONTROLLED THERMONUCLEAR RESEARCH QUARTERLY REPORT FOR JUNE, JULY, AUGUST 1959

Abstract

S>Pyrotron Program: The efforts of the group were concentrated on injection studies and on the analysis of plasmas produced by slow magnetic compression. Results included: (1) more detailed analysis of trapped plasmas, showing the effect of magnetic field intensity; (2) the determin- ation of radial distributions of the escaping electron fluxes in Table Top, from which information on radial plasma diffusion can be gleaned, showing that the indicated role of radial diffusion is very small and that the plasma density falls rapidly to a very small value outside a central cere about l 1/2 in. in diameter; (3) the refinement of buildup calculations for the ALICE energetic neutral injection experiment, showing the role of the chamber wall in the build-up and establishing limits on the required pumping. High-energy Injection: The high-energy molecular ion injection scheme involves the use of an axial arc to dissociate the molecular ions. The presence of an arc in the center of a hot plasma will cause a serious drain on the hot ions, via the low-energy electrons in the arc. In order to determine the effect of this energy loss upon the build-up of a hot plasma, the build-up equations were modified to take accountmore » of this energy loss. In the Beta-ray Experiment the steady-state bias curves and containment-time measurements were extended to other scattering gases (Ar and Xe). Work on the Bumpy Torus and the Von Ardenne type ion source is reported. Astron Program: In the preceding report a new injection method for the E-layer electrons was mentioned. The theory and the calculations required to evaluate this method were developed during the quarter. The basic idea of the method is to allow the electrons to slide within a potential well while simultaneously losing energy to a suitable arrangement of passive circuits. Astron E-layer calculations are summarized. In the Astron d-c test some minor modifications to the accelerating column of the electron gun resulted in a marked increase in reliability and in much longer periode of operation between shutdowns to clean insulators. Pinch Program: Work is summarized on the linear hard-core pinch, the Levitron, electron beam experiment, plasma accelerator experiments, matrix Marx bank, the 4-inch tubular pinch, switches, the 10-inch Triax, ribbon pinch, Homopolar III diagnostic studies, viscous effects in highly ionized rotating plasmas, and piezoelectric probes. Theoretical Research: A two-pronged series of numerical calculations is being carried out which bears on the general problem of the loss rate of ions due to ion-ion interactions in mirror geometry. A plasma Fokker- Planck equation code, DION, for slowing down of fast ions in a plasma is described whichemploys an implicit difference scheme and a variable energy mesh size. Basic Experimental Research: Several experiments that involve partially ionized gases are being worked on, partly to aid in the evaluation of phenomena occurring in the devices that produce warm, fully iorized plasmas. Two of these experiments are described. Hydromagnetic wave properties such as velocity, attenuation, impedance, and energy transfer were measured in a cylindrical plasma. Results are compared with theoretical discussions of Alfven-wave propagation under similar conditions. Experiments on ion-cyclotron resonance heating were continued using a hollow cylinder of plasma, formed by a reflex discharge, in a magnetic mirror. Engineering and Technological Development:. Work is summarized on ultra-high vacuum, cryogenic pumping, mechanical engineering, and electrical engineering. (For preceding period see UCRL-8775.) (W.D.M.)« less