1. Code Name: BALLOON

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

3. Responsible Physicist: M. Chance

4. Others involved in code development: J. Manickam, R. Dewar.

5. One line description: Ballooning mode infinite-n stability of tokamaks - critical-n, local shear.

6. Computer systems which code runs on: Cray . Typical running time (if applicable): ~ 10 sec./surface

8. Approximate number of code lines: 2200

9. Does this code read data files from another code? Reads MAPDSK, MPOUT1 from mapping codes.

10. Does this code produce data files that can be read by another code? No.

11. 1-2 paragraph description of code: Integrates the 2nd order ODE to find ballooning stability limits and the critical-n from a WKB approximation. The Mercier criterion is calculated and a choice of K.E. norm is available. Output includes contours of local magnetic shear, curvature, and dw contributions from the various driving terms.

12. Similar codes to this code, and distinguishing differences: Most institutions have their own version.

13. Journal References describing code

14. New code capabilities planned for next 1-2 years:

15. Code users: PPPL MHD group, MIT.

16. Present and recent applications of code: The code is used for almost every linear MHD parameter study at PPPL.

17. Status of code input/output documentation. Check one:

(X) does not exist

( ) incomplete

( ) exists

18 Year Code was first used and present frequency of use: 1978

19. Estimate of Man-Years invested in developing code: 1-2

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

( ) physics module to be used in integrated moddelling

(X) code for machine design

21.Language code is writen in: Fortran

22. Results of intercomparisons with other codes and results of validation against experiments. Consistent and accurate with other codes. Experimentally consistent within the ideal MHD model.