1. Code Name: QSOLVER

2. Category: IIa. Plasma Equilibrium: 2D Fixed Boundary

3. Responsible Physicist: S. C. Jardin

4. Others involved in code development: D. Monticello, M. Chance

5. One line description: Fixed boundary MHD equilibrium code with prescribed p and q profiles.

6. Computer systems which code runs on: NERSC Cray computers

7. Typical running time (if applicable): 1-30 minutes

8. Approximate number of code lines: 5000

9. Does this code read data files from another code? No

10. Does this code produce data files that can be read by another code? If so, explain. Yes, it writes an EQDISK file to be read by the MAPPER code.

11. 1-2 paragraph description of code: This code uses the iterative metric method (see ref in 13) to simultaneously solve for a plasma equilibrium and the magnetic flux coordinates while keeping the safety factor profile and plasma pressure fixed.

12. Similar codes to this code, and distinguishing differences: Similar to JSOLVER, but keeps q-profile fixed rather than surface averaged current density.

13. Journal References describing code

: DeLucia, J., Jardin, S. C., Todd, A. M. M., J. Comput Phys. 37 2 (1980).

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

15. Code users: M. Chance, J. Manickam, D. Monticello 16. Present and recent applications of code: Second stability studies, TFTR stability studies, reversed shear studies

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

18. Year Code was first used and present frequency of use: First used in 1978, but upgraded and improved several times since then. Code is now used extensively in stability studies.

19. Estimate of Man-Years invested in developing code: probably 2-3 in both first developing and subsequently improving code

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

( ) code for machine design

21. Language code is writen in: FORTRAN

22. Results of intercomparisons with other codes and results of validation against experiments. This code has recently been validated against POLAR2D and SESC