**MH3D-T CODE FACT SHEET **** **

1. Code Name: MH3D-T

2. Category: Two Fluid, 3D Toroidal Initial Value

3. Responsible Physicist: Linda E. Sugiyama

4. Others involved in code development: W. Park, G.Y. Fu, X-Z. Tang, PPPL, H.R. Strauss, NYU

5. One line description: Two fluid initial value code for 3D toroidal geometry

6. Computer systems which code runs on: Cray J-90/SV1, CM-5, Workstations including HP750 and Dec Alpha

7. Typical running time: several to tens of hours on C-90, in the nonlinear phase; depends strongly on the accuracy/resolution required

8. Approximate number of code lines: 40K

9. Does this code read data files from another code? yes, MH3D, MH3D-K, PEST

10. Does this code produce data files that can be read by another code? yes, MH3D, MH3D-K

11. 1-2 paragraph description of code: This code incorporates a nonlinear model for the solution of the two fluid equations in a full 3D torus. It is the first two fluid, initial value code in a non-reduced geometry. It includes the neoclassical parallel viscous stress (neoclassical MHD) terms. The most recent extension evolves the anisotropic pressure/temperature, components T_parallel and T_perp, for each species. The basic two-fluid equations are based on the drift ordering, originally derived for small perturbations, to arbitrary perturbation size. It is similar, but not identical to, the Braginskii equations. It includes diamagnetic drifts, the ion gyroviscous stress tensor, Hall terms and electron pressure gradient in the Ohm's law, and temperature evolution, including parallel thermal conductivity. Neoclassical parallel viscous force terms, that affect the poloidal rotation, the neoclassical resistivity, and bootstrap current are being added. The code is intended to run in various limits, to enable greater physical insight and a closer connection with analytical work. These include resistive and ideal MHD, a 4-field model (Hazeltine, Hsu, Morrison), and the ability to turn off parts of the two fluid model. All these models use limits of the same equations. In addition, these equations can be solved in a number of different geometries, such as full 3D toroidal, 2D cylinder, and a number of different symmetry limits.

12. Similar codes to this code, and distinguishing differences: MH3D, resistive MHD initial value code in 3D toroidal geometry, is a single fluid code that formed the basis for this one.

13. Journal References describing code (up to 3): W. Park, ..., L. Sugiyama, et al., Phys. Fluids B 4 2033 (1992). L.E. Sugiyama and W. Park, submitted to Phys. Plasmas (1999).

14. New code capabilities planned for next 1-2 years: test anisotropic pressure/temperature time evolution and compare to neoclassical theory, investigate possible closures for the heat flux. Combine with general geometry and massively parallel versions.

15. Code users: L. Sugiyama, W. Park (PPPL), G.Y. Fu (PPPL), H.R. Strauss (NYU)

16. Present and recent applications of code: Benchmarked against ion diamgnetic stabilization of m=1, n=1 mode. Applied to problem of plasma rotation in cylinder and torus (poloidal and toroidal). Demonstrated basic neoclassical tearing mode behavior. Investigation of magnetic island development, including parallel and perpendicular thermal conductivites.

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

18 Year Code was first used and present frequency of use: 1995; frequent

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

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, some C

22. Results of intercomparisons with other codes and results of validation against experiments. Two fluid part benchmarked against numerical solution of analytic dispersion relation for m=1, n=1 mode in a cylinder - excellent agreement over wide range of growth rate. Two fluid nonlinear evolution and rotation of m>1 magnetic islands in a cylinder have been shown to agree with previous analytic and numerical results MHD part previously well tested.