Subroutines for some plasma surface interaction processes: physical sputtering, chemical erosion, radiation enhanced sublimation, backscattering and thermal evaporation*1

Abstract

A suite of FORTRAN subroutines/functions to generate data using empirical formulas for physical sputtering of mono-atomic targets for any elemental incident ion (atom), chemical erosion of graphite, Radiation Enhanced Sublimation (RES) of graphite, the number and energy backscattering coefficients for any elemental incident ion (atom) on a compound target and thermal evaporation of graphite is presented. Since chemical erosion, RES and thermal evaporation depend on the surface temperature of graphite, a subroutine implementing the 1-D heat diffusion equation to determine the temperature of any plasma-facing graphite surface is implemented. As an example to illustrate the use of these subroutines/functions, a simple model for the erosion of a plasma-facing surface, consisting of a simple collisionless sheath model, a 1-dimensional steady state heat diffusion model and 0-dimensional steady state particle balance at the target is developed and a sample listing of the program is presented. Title of program: Plasma Surface Interaction Codes (PSIC) Catalog identifier: ADTR Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADTR Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computers for which the program has been designed for and others on which it has been tested: Program is designed for any computer with a FORTRAN-77 compiler. It has been tested on a Linux PC with g77, Absoft f77, f90, f95, Fujitsu f95, Lahey f95 Operating systems under which the program has been tested: Linux, UNIX Programming language used: FORTRAN-77 Memory required to execute with typical data: Negligible (executable is 178 861 bytes; add to it the memory used by the Fortran library linked to) No. of bits in a word: 16 No. of processors used: 1 Has the code been vectorized or parallelized?: No No. of bytes in distributed program, including test data, etc.: 11 619 No. of lines in distributed program, including test data, etc.: 1015 Distribution format: tar gzip file Nature of physical problems: 0-D plasma surface interaction model used to demonstrate calls to subroutines for physical sputtering yield, chemical erosion yield of graphite, RES of graphite, backscattering coefficients, thermal evaporation of graphite and 1-D heat diffusion in graphite. Method of solution: Semi-empirical formulas are used for the PSIs and analytical formulas are used for thermal evaporation and 1-D heat diffusion in graphite. Restrictions on the complexity of the problem: All the PSIs (except for the backscattering coefficients) are valid only for a monoatomic target. The heat diffusion solution is not valid for non-uniform plasmas and for targets for which the heat diffusion is not isotropic. Typical running time: Example program takes much less than 0.01 second Universal features of the program: None