A formula for efficiency of fast wave current drive in fusion devices
- General Atomics, San Diego, CA (United States)
- Princeton Univ., NJ (United States). Plasma Physics Lab.
- California Univ., Los Angeles, CA (United States). School of Engineering and Applied Science
Fast wave current drive (FWCD) is a principal candidate for non- inductive current drive schemes in reactors. Major experiments are in progress or planned on DIII-D, JET, and Tore-Supra. A theory for FWCD was presented by two of the authors and collaborators. To minimize computations required in transport simulations, and for analytical understanding, it is very useful to have a concise analytical efficiency formula. Fisch and Karney, and Ehst and Karney have obtained empirical formulae that fits numerical results for the Landau limit and Alfven limit; the latter fits results at 1 < Z{sub i} {le} 2. This paper extends a previous numerical study on FWCD at arbitrary frequencies and Z{sub i}. Analytical formulae for FWCD efficiency, valid for all frequencies and Z{sub i}, are derived using the adjoint technique in high and low phase velocity regions. A smooth patching between the two regions produces an analytical formula which is accurate for all frequencies, Z{sub i}, and phase velocities. Comparison with existing results will be discussed. A corollary of the present calculation is that a low phase velocities and in the Landau limit, the efficiency is the same as that calculated from the Lorentz model collision operator.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER53277; AC02-76CH03073
- OSTI ID:
- 5068087
- Report Number(s):
- GA-A-20873; CONF-920717-1; ON: DE92016152
- Resource Relation:
- Conference: Topical conference meeting on radio frequency heating and current drive of fusion devices, Brussels (Belgium), 7-10 Jul 1992
- Country of Publication:
- United States
- Language:
- English
Similar Records
Efficiency of fast wave current drive for a weakly relativistic plasma
Efficiency of fast wave current drive for a weakly relativistic plasma