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NESC0749 STEEP4

STEEP-4, Fusion Reaction Rates for Maxwellian and Slowing-Down Plasma Ion Distribution

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1. NAME OR DESIGNATION OF PROGRAM:  STEEP4.
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2. COMPUTERS
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Program name Package id Status Status date
STEEP-4 NESC0749/01 Tested 02-JUL-1985

Machines used:

Package ID Orig. computer Test computer
NESC0749/01 CDC 7600 CDC CYBER 740
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3. DESCRIPTION OF PROBLEM OR FUNCTION

STEEP4 calculates fusion reaction rates in terms of the specific reactivity (sigma-v) which is the product of cross section and relative velocity averaged over the actual ion distributions of the interacting particles in the plasma. Maxwellian ion distributions are modified to include slowing-down contributions which are characterized in terms of plasma parameters. Rapid and accurate algorithms are used for integrating the specific reactivity from spectra and input cross sections. Options are also provided for rapid calculation of screening effects on specific reaction rates.
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4. METHOD OF SOLUTION

The main program uses the method of steepest descent. However, options are provided to use Gauss-Hermite and dense trapezoidal quadrature integration techniques. Gamow penetration form, log-log interpolation, and cubic interpolation routines are used to provide interpolated values of cross sections for the integration routines. Slowing-down contributions are included by joining a 1/E ion slowing-down distribution smoothly to a background Maxwellian distribution for the total ion distribution. Multiplicative screening factors are calculated from plasma parameters using weak-, intermediate-, and strong- screening formulations.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The form of the slowing-down distribution neglects absorption and leakage of plasma particles during the slowing-down process and is based on the assumption that the slowing-down ion is faster than the background ions but slower than the plasma electrons. Spatial and angular dependences of the ion distributions are not treated in this version of the code.
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6. TYPICAL RUNNING TIME

The program requires about 0.1 second for specific reactivity evaluation without slowing-down or screening corrections for each set of plasma parameters when run on the CDC7600. The additional time for screening factor calculation is negligible; however, each slowing-down evaluation requires 10 to 20 seconds.
NESC0749/01
NEA-DB executed the test case included in this package  on CDC CYBER 740 in 1504 seconds of CPU time.
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7. UNUSUAL FEATURES OF THE PROGRAM

STEEP4 is modularly structured so that selected sections may be removed for incorporation in thermonuclear burn codes to provide rapid and yet relatively accurate in-line specific reactivity computation. The options to include slowing-down and screening effects provide a great deal of flexibility and increase the range of applicability of the code. Also a subroutine is provided to read input cross-section data from an assumed library of charged-particle cross sections.
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8. RELATED AND AUXILIARY PROGRAMS

STEEP4 uses the LASL program library subroutine PLOTM (reference 2) to generate SC4020 film plot output.
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9. STATUS
Package ID Status date Status
NESC0749/01 02-JUL-1985 Tested at NEADB
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10. REFERENCES

- D. R. Harris, D. E. Dei, A. A. Husseiny, Z. A. Sabri, and G. M. Hale: The STEEP4 Code for Computation of Specific Thermonuclear Reaction Rates from  Pointwise Cross Sections, LA-6344-MS, June 1976.
- R. Frank, PLOTM - Standardized Plot on Film with Tic Marks, Los Alamos Scientific Laboratory Programmer's Information Manual, LA-5525-M, Vol. 2, 1974.
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11. MACHINE REQUIREMENTS

A SC4020 Film Unit is used to provide film plotting capability.
NESC0749/01
The test case required on CDC CYBER740 70,400 (octal) words of main storage.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0749/01 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:   SCOPE 2.1.3.
NESC0749/01
NOS 1.4-531 (CDC CYBER 740).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHORS

                 D. R. Harris and G. M. Hale
                 Los Alamos Scientific Laboratory
                 P. O. Box 1663
                 Los Alamos, New Mexico  87545
                 A. A. Husseiny and Z. A. Sabri
                 Iowa State University of Science and Technology
                 Ames, Iowa  50010
                 D. E. Dei
                 Carnegie-Mellon University
                 5000 Forbes Avenue
                 Pittsburgh, Pennsylvania  15213
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16. MATERIAL AVAILABLE
NESC0749/01
File name File description Records
NESC0749_01.003 INFORMATION FILE 41
NESC0749_01.004 JCL INFORMATION 8
NESC0749_01.005 STEEP-4 SOURCE PROGRAM (FORTRAN) 2191
NESC0749_01.006 STEEP-4 TEST CASE INPUT DATA 134
NESC0749_01.007 STEEP-4 TEST CASE PRINTED OUTPUT 1233
NESC0749_01.008 STEEP-4 TEST CASE PUNCHED OUTPUT 54
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17. CATEGORIES
  • X. Magnetic Fusion Research

Keywords: ENDF/B, cross sections, reaction kinetics, thermonuclear reactions.