1. Code Name: ORBIT

2. Category: VIa. Kinetic: Particle Orbits

3. Responsible Physicist: R. B. White

4. Others involved in code development: None

5. One line description: Hamiltonian guiding center Monte Carlo with numerical or analytic equilibria.

6. Computer systems which code runs on: all Unix platforms

7. Typical running time (if applicable): 30 sec for 1000 particles 100 transits

8. Approximate number of code lines: ~ 3000

9. Does this code read data files from another code? . Can read equilibrium data from mapping codes.

10. Does this code produce data files that can be read by another code? Yes, lost particle data files for analysis

11. 1-2 paragraph description of code: Hamiltonian guiding center particle motion including use of numerical equilibrium and field perturbations for analyzing test particle transport, especially energetic ions uses flux coordinates.

12. Similar codes to this code, and distinguishing differences: Tani (Japan), Hively (ORNL), Haegi (Italy), guiding center codes but not Hamiltonian.

13. Journal References describing code (up to 3): R. B. White and M. S. Chance, Phys. Fluids B, 2455 (1984), R. B. White, Canonical Hamiltonian Guiding Center Variables, Phys Fluids B, 845 (1990), R. B. White and A. H. Boozer, Rapid Guiding Center Calculations, Phys. Plasmas 2915 (1995)

14. New code capabilities planned for next 1/2 years: Improved stochastic ripple loss prediction ability.

15. Code users: Sigmar, Hsu (MIT), Heidbrink (GA), M. Redi (PPPL), Stuart Zweben (PPPL), Princeton Thesis students Duvall, Albert, Yi Zhao, Y. Wu, Y. Chen,

16. Present and recent applications of code: Alpha loss due to TAE mode (Hsu), Stochastic Ripple Loss in TFTR, ITER, TAE induced ripple loss.

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: 1984, daily

19. Estimate of Man-Years invested in developing code: 5

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 modelling (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. See Self-Consistent Study of the Alpha Particle Driven TAE Mode Y. Wu and R. B. White Princeton University, Plasma Physics Laboratory Report PPPL-2984 (April 1994) 27 pp. Phys. Plasmas , (8), 2733-2740 (1994) Study of Stochastic Toroidal Field Ripple Losses of Charges Fusion Products at the Midplane of TFTR R. L. Boivin, S. J. Zweben, and R. B. White Nucl. Fusion , (3) 449-465 (1993) Collisional Stochastic Ripple Diffusion of Alpha Particles and Beam Ions on TFTR M. H. Redi, M. C. Zarnstorff, R. B. White, R. V. Budny, J. F. Schivell, S. D. Scott, A. Janos, and J. Zweben Princeton University, Plasma Physics Laboratory Report PPPL-3011-R (July 1995) 62 pp. submitted for publication to Nucl. Fusion (1994) Nonlinear Evolution of the Alpha Particle Driven Toroidicity- Induced Alfven Eigenmode Y. Wu, R. B. White, Y. Chen, and M. N. Rosenbluth Princeton University, Plasma Physics Laboratory Report PPPL-3103 (June 1995) 34 pp., Phys. Plasmas 2, 4555 (1995) Toroidal Alfven Eigenmode-Induced Ripple Trapping, R. B. White, E. Fredrickson, D. Darrow, M. Zarnstorff, R. Wilson, S. Zweben, K. Hill, Yang Chen, Guoyong Fu, PPPL-3090 (March 1995) 12 pp. Phys. Plasmas 2, 2871 (1995)