Conservative Differencing of the Electron Fokker-Planck Transport Equation (open access)

Conservative Differencing of the Electron Fokker-Planck Transport Equation

We need to extend the applicability and improve the accuracy of kinetic electron transport codes. In this paper, special attention is given to modelling of e-e collisions, including the dominant contributions arising from anisotropy. The electric field and spatial gradient terms are also considered. I construct finite-difference analogues to the Fokker-Planck integral-differential collision operator, which conserve the particle number, momentum and energy integrals (sums) regardless of the coarseness of the velocity zoning. Such properties are usually desirable, but are especially useful, for example, when there are spatial regions and/or time intervals in which the plasma is cool, so that the collision operator acts rapidly and the velocity distribution is poorly resolved, yet it is crucial that gross conservation properties be respected in hydro-transport applications, such as in the LASNEX code. Some points are raised concerning spatial differencing and time integration.
Date: January 12, 1981
Creator: Langdon, A. B.
Object Type: Article
System: The UNT Digital Library
UNSPEC: revisited (semaphore code). [For CDC 7600] (open access)

UNSPEC: revisited (semaphore code). [For CDC 7600]

The UNSPEC code is used to solve the problem of unfolding an observed x-ray spectrum given the response matrix of the measuring system and the measured signal values. UNSPEC uses an iterative technique to solve the unfold problem. Due to experimental errors in the measured signal values and/or computer round-off errors, discontinuities and oscillatory behavior may occur in the iterated spectrum. These can be suppressed by smoothing the results after each iteration. Input/output options and control cards are explained; sample input and output are provided. (RWR)
Date: January 12, 1981
Creator: Neifert, R.D.
Object Type: Report
System: The UNT Digital Library
Low-Cost Solar Array Project. Task I. Silicon Material: Investigation of the Hydrogenation of SiCl/sub 4/. Seventh Quarterly Report (open access)

Low-Cost Solar Array Project. Task I. Silicon Material: Investigation of the Hydrogenation of SiCl/sub 4/. Seventh Quarterly Report

Research and development work on the hydrochlorination of SiCl/sub 4/ and m.g. silicon metal to SiHCl/sub 3/ is reported. Activities include a series of experiments to study the life of the Si mass bed. The effect of prolonged reaction on the rate of the hydrochlorination reaction was studied, and a material balance on the reaction was made. A corrosion study was made on Incoloy 800 as the selected material of construction for the hydrochlorination reactor in the Union Carbide EPSDU. (WHK)
Date: January 12, 1981
Creator: Mui, Jeffrey Y. P.
Object Type: Report
System: The UNT Digital Library
High resolution, low cost solar cell contact development. Quarterly technical progress and schedule report for the period ending December 31, 1980. CDRL 4 (open access)

High resolution, low cost solar cell contact development. Quarterly technical progress and schedule report for the period ending December 31, 1980. CDRL 4

The scope of the contract covers the development and evaluation of forming solar cell collector grid contacts by the MIDFILM process. This is a proprietary process developed by the Ferro Corporation which is a subcontractor for the program. The MIDFILM process attains line resolution characteristics of photoresist methods with processing related to screen printing. The surface to be processed is first coated with a thin layer of photoresist material. Upon exposure to ultraviolet light through a suitable mask, the resist in the non-pattern area cross-links and becomes hard. The unexposed pattern areas remain tacky. The conductor material is applied in the form of a dry mixture of metal and frit particles which adher to the tacky pattern area. The assemblage is then fired to ash the photo-polymer and sinter the fritted conductor powder. Progress is reported. (WHK)
Date: January 12, 1981
Creator: Garcia, A.
Object Type: Report
System: The UNT Digital Library