1. Code Name: VACUUM

2. Category: VIIa. Linear Stability: 2D Ideal

3. Responsible Physicist: M. S. Chance

5. One line description: Vacuum contribution to MHD stability codes.

6. Computer systems which code runs on: Cray and Work Stations

7. Typical running time (if applicable): 10-60 sec./case

8. Approximate number of code lines: 16,000

9. Does this code read data files from another code? yes, MAPDSK and MPOUT1 and other mapping codes, and eigenfunctions from stability codes like PEST and GATO for constructing eddy currents in conducting shells and Mirnov loops.

10. Does this code produce data files that can be read by another code? Yes. Stability codes reads dW_v as a function of the perturbed radial magnetic field for the vacuum contribution to dW. It is interfaced to the PEST and NOVA series of codes and also DCON and GATO.

11. 1-2 paragraph description of code: The magnetic scalar potential is solved from Laplace's equation using a collocation-Green's function method to calculate the vacuum contribution to dw for for three topologically distinct wall shapes - toroidal, spherical, and segmented. It calculates the vacuum response in either a Fourier or a Finite representation in the poloidal angle. It also reads the output from stability codes and calculates the eddy current pattern on the shells and also simulates the Mirnov loop readings. A thin resistive shell is now an option and the coding for feedback simulations is being added.

12. Similar codes to this code, and distinguishing differences: ERATO's and GATO's vacuum code also solves for the scalar potential but uses finite elements on the plasma surface. A later version solves for the magnetic vector potential throughout the vacuum region.

13. Journal References describing code: 8th Conference on Numerical Simulations of Plasmas, Monterey, CA (1978).

Phys. Plasmas(4) 2161-2180, June, 1997.

Postprint in /u/chance/Tex/Papers/Vacuum/Revtex/vacuum_2col.[tex, dvi, ps]

14. New code capabilities planned for next 1-2 years: Modification to add effects of finite resistivity in the shell, and feedback capabilities.

15. Code users: PPPL's PEST and NOVA codes. GA's GATO and ADJ code. DCON

16. Present and recent applications of code: Stability studies on PBX-M, TFTR, TPX, NSTX, DIII-D, CMOD

17. Status of code input/output documentation. Check one: ( ) does not exist ( ) incomplete (X) exists.

See /u/chance/Tex/Papers/Vacuum/Revtex/vac_manual.[tex, dvi, ps]

18 Year Code was first used and present frequency of use: 1977, Used daily.

19. Estimate of Man-Years invested in developing code: 2 yrs and still being constantly updated.

20. Catagories of usage of Code (Check all that apply): (X) application code to do analysis and prediction of experiments (X) numerical testbed of theoretical ideas (X) physics module to be used in integrated moddelling (X) code for machine design

21. Language code is writen in: Fortran, Fortran 90

22. Results of intercomparisons with other codes and results of validation against experiments. Excellent comparison with analytical models and other codes like GATO.