BALLOON

1. Code Name: Balloon
2. Code Category: MHD
3. Primary Developer: Morrell Chance
4. Other Developers and Users: Bob Dewar, J. Manickam. Users: PPL MHD group
5. Short description (one line if possible): Calculates infinite-n ballooning tokamak stability and estimate critical n for marginal stability.
6. Computer Language: Fortran, 4000 lines
7. Type of input required (including files and/or output from other codes). Is there any special input preparation system (eg, GUI): Namelist for control, binary (C ) (ZIO interface wrap) or ASCII input depending on codes. Is there any special input preparation system (eg, GUI): No
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). Also has output graphic files for for Gnuplot and MatLab.
9. Describe any postprocessors which read the output files: Gnuplot and MatLab.
10. Status and location of code input/output documentation SWIM SVN repository.
11. Code web site? SWIM
12. Is code under version control? What system? Is automated regression testing performed? SWIM SVN
13. One to two paragraph description of equations solved and functionality including what discretizations are used in space and time Solves the infinite-n ballooning equation with finite shear using 4th order Runge-Kutta method. Also calculates the Mercier Criterion and local shear properties of the equilibrium as well as the n number for marginal stability.
14. What modes of operation of code are there (eg: linear, nonlinear, reduced models, etc ) Purely linear.
15. Journal references describing code: No specific journal article. Relevant physics articles may be: Theory of ballooning modes in tokamaks with finite shear, D. Dobrott, D. B. Nelson, J. M. Greene, A. H. Glasser, M. S. Chance and E. A. Freeman. Phys. Rev. Letters, Vol. 39, No. 15 (1977) 943-946. The second region of stability against ballooning modes, J. M. Greene and M. S. Chance. Nucl. Fusion, Vol. 21, No. 4 (1981) 453-464. n-dependence of ballooning instabilities, R. L. Dewar, J. Manickam, R. C. Grimm, M. S. Chance. Nuclear Fusion, Vol. 21, No. 4 (1981) 493-498
16. Codes it is similar to and differences (public version): CAMINO. This code calculates the ballooning s-alpha diagram based on the Green-Chance paper. No finite n calculations.
17. Results of code verification and convergence studies (with references): Verified with PEST-II for finite n. With CAMINO for infinite n.
18. Present and recent applications and validation exercises (with references as available)
19. Limitations of code parameter regime (dimensionless parameters accessible)
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? Describe. 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