Modeling cross-field drifts and current with the B2 code for the CIT divertor (open access)

Modeling cross-field drifts and current with the B2 code for the CIT divertor

We have modified the B2 edge-plasma code to include the effects of classical fluid drifts across the magnetic field lines and plasma currents. This report presents preliminary results of these effects for the CIT parameter regime. The basic plasma model described by Braams involves solving the continuity equation, the parallel momentum balance equation, and separate energy balance equations for the ions and the electrons. If multiple ion species are present, they are all assumed to have a common temperature, but their densities and parallel velocities are solved for using additional continuity and parallel momentum balance equations for each species. Momentum and heat transport parallel to the magnetic field, B, are given by the classical collisional theory. On the other hand, transport perpendicular to B is represented by anomalous diffusion coefficients which are adjusted to agree with experimental measurements. These transport coefficients are generally taken to be constant in radius and poloidal angle, although this is not necessary. The goal of our work has been to include both the classical cross-field drift terms and the effects of parallel currents in the equations used in the B2 code. The motivation for including the cross-field terms comes from simple model calculations which indicate …
Date: October 12, 1990
Creator: Rognlien, T. D.; Milovich, J. L. & Rensink, M. E.
Object Type: Report
System: The UNT Digital Library
Performance of a 500 watt Nd:GGG zigzag slab oscillator (open access)

Performance of a 500 watt Nd:GGG zigzag slab oscillator

Realization of practical multi-kilowatt Nd:garnet lasers will require the scale-up of crystal dimensions as well as more powerful pumping sources. A high average power zigzag slab crystal amplifier testing facility has been established at LLNL which employs two 100 kW{sub e} vortex stabilized arc lamps, cooled reflectors and a cooled, spectrally filtered, crystal slab mounting fixture. The operational characteristics of the first crystal laser to be tested in this setup, a Nd:GGG zigzag oscillator, are presented. A Nd:GGG crystal of dimensions 18 {times} 7 {times} 0.5 cm{sup 3}, doped at 2 {times} 10{sup 20} cm{sup {minus}3} Nd{sup 3+} atomic density, was pumped by up to 40 kW of filtered argon line emission. A small-signal single pass gain (losses excluded) of 1.09 was measured with a probe laser when the DC input to the lamps was 43 kW{sub e}. Our power supply was then modified to operate in a pulsed mode and provided one to three milliseconds pulses at 120 Hz. An average optical output power of 490 watts was obtained at a lamp input power of 93 kW{sub e} in an unoptimized resonator. The laser output power declined after a few tens of seconds since the slab tips were not …
Date: January 12, 1990
Creator: Zapata, L.; Manes, K. R.; Christie, D.; Davin, J.; Blink, J.; Penland, J. et al.
Object Type: Article
System: The UNT Digital Library
Evaluation of superconducting wiggler designs and free-electron laser support: Final report (open access)

Evaluation of superconducting wiggler designs and free-electron laser support: Final report

This report consists of copies of previous progress reports, and copies of viewgraphs presented in a talk at Los Alamos. The report describes activities carried out as part of a project to evaluate the design and performance of a superconducting wiggler magnet design. It includes work on evaluating the appropriate materials for the magnet coils and poles, and stress evaluations for the design. It includes work on beam optics through the magnet, and design considerations to optimize extraction: work on the cryocooling system; weight minimization efforts; and design work on the vacuum liner for the magnet. A major concern in all of this design work is heat loads which will be dissipated in different parts of the system during operation, as well as transient events.
Date: October 12, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
1990 Fischer Standard study (open access)

1990 Fischer Standard study

The purpose of this work is to develop a set of Titanium areal density standards for calibration and maintenance of the Fischer`s X-ray Fluorescence measurement system characterization curve program. The electron microprobe was calibrated for Titanium films on ceramic substrates using an existing set of laboratory standards (Quantity: 6 Range: 0.310 to 1.605). Fourteen source assemblies were measured and assigned values. These values are based on a mean calculation, of five separate readings, from best curve fit equations developed form the plot of the laboratory standards areal density (Source Measure) versus electron microprobe measurement (reading). The best fit equations were determined using the SAS General Linear Modeling (GLM) procedure. Four separate best fit equations were evaluated (Linear, Quadratic, Cubic and Exponential). Areal density values for the Fischer Standards appear here ordered by best fit equation based on maximum R{sup 2}.
Date: September 12, 1990
Creator: Roubik, G. J.
Object Type: Report
System: The UNT Digital Library