1. Code Name: VACUUM
2. Code Category: MHD
3. Primary Developer: Morrell Chance
4. Other Developers and Users: Alan Glasser, J-K. Park, Nate Ferraro, Neil Pomphrey, J. Manickam, Ming Chu.
5. Short description (one line if possible): Calculates the perturbed magnetic field in the vacuum region of Tokamaks and on the nearby conductors.
6. Computer Language: Fortran, Fortran77, roughly 27,000 lines
7. Type of input required. Is there any special input preparation system (eg, GUI): Namelist for control, binary (C ) (ZIO interface wrap) or ASCII input depending on codes. Requires resistive wall eigenfunctions for RWM calcualtions, otherwise no other special input preparation required.
8. Type of output produced (including files that are read by other codes and sizes of large files and synthetic diagnostics): ASCII outputs for interfacing other codes. Code has built-in graphics (TV80 wrap on NCARG)
9. Describe any postprocessors which read the output files: Circuit equations module for RWM calculations.
10. Status and location of code input/output documentation: Manual (2006) for the code at: /u/chance/Tex/Papers/Vacuum/Revtex/vac_manual.pdf. Needs to be updated.
11. Code web site?
12. Is code under version control? Yes. What system? SVN. Is automated regression testing performed? No
13. One to two paragraph description of equations solved and functionality including what discretizations are used in space and time: VACUUM solves Laplace's equation for the magnetic scalar potential with Neumann boundary conditions on the plasma and external conductors. It uses Fourier harmonics in the toroidal and poloidal coordinates, with a finite element option in the poloidal coordinate being implemented. RWM capability when interfaced with the Circuit equations module. It has capabilities for modeling the Mirnov measurements and calculating the induced currents on the conductors.
14. What modes of operation of code are there (eg: linear, nonlinear, reduced models, etc ): VACUUM is purely linear.
15. Journal references describing code: "Vacuum calculations in azimuthally symmetric geometry", M. S. Chance. Phys. Plasmas 4 (1997) 2161-2180.
"Normal mode approach to modelling of feedback stabilization of the resistive wall mode", M. S. Chu, M. S. Chance A. H. Glasser and M. Okabayhashi. Nucl. Fusion 43 (2003) 441-454. "Theoretical modelling of the feedback stabilization of external MHD modes in toroidal geometry", M. S. Chance, M. S. Chu, M. Okabayashi and A. D. Turnbull. Nucl. Fusion 42 (2002) 295-300.
16. Codes it is similar to and differences (public version): Not sure.
17. Results of code verification and convergence studies (with references): VACUUM has been used as the vacuum component is a variety of codes (PEST, DCON, M3D-C1, IPEC, etc.) all of which has been successfully through the verification and validation processes. It has also been checked with simple analytic (cylindrical and elliptical cross section) models.
18. Present and recent applications and validation exercises (with references as available): See item 17. VACUUM is also being applied to the error field studies on ITER. A successful check preliminary to these calculations devised by Neil Pomphrey was against the analytical fields from virtual toroidal surfaces on which the normal fields originated from a tilted straight current carrying wire model. This validated and verified both the surface and volume field calculations of the code. See: "Final Report: Task on Error Field Measurement on ITER Without Plasma". ITER Task Number C19TD24FU. March 2011. M. G. Bell, N. Pomphrey, M. S. Chance, S. P. Gerhardt, D. Mueller and A. Boozer.
19. Limitations of code parameter regime (dimensionless parameters accessible) : Toroidally symmetric geometry. Only up to 2 external conductor segments.
20. What third party software is used? (eg. Meshing software, PETSc, ...): Usual mathematical libraries, e.g., NAG
21. Description of scalability: NA
22. Major serial and parallel bottlenecks. NA
23. Are there smaller codes contained in the larger code? No
24. Supported platforms and portability: Linux (portals)
25. Illustrations of time-to-solution on different platforms and for different complexity of physics, if applicable: Seconds.