Dependence of Bootstrap Current, Stability, and Transport on the Safety Factor Profile in DIII-D Steady-State Scenario Discharges
Conclusions of this report are: (1) In our scans of q{sub min} and q{sub 95}, the bootstrap current fraction increased with q{sub 95} but did not continue to increase with q{sub min} above about 1.5 as expected by f{sub BS} {approx} q{beta}{sub N}; (2) With existing control tools, q{sub min} {approx} 1.5 appears optimal for maximizing bootstrap current if the calculated ideal wall limit can be reached (only narrowly more so than q{sub min} {approx} 1.1); (3) q{sub min} {approx} 2 discharges achieved lower {beta}{sub N} and calculated n = 1 {beta}{sub N} limits, had increased transport, lower density, lower temperature gradients, and as a result did not produce as much bootstrap current; (4) Highest f{sub BS} achieved at highest q{sub 95} (=6.8), but scan suggests lower q{sub 95} is required for more reactor relevant fusion gain G {approx} {beta}{sub N}H{sub 89}/q{sub 95}{sup 2}; (5) New tools (off-axis NBI, more ECCD) may allow access to higher {beta}{sub N} limits and higher bootstrap fractions.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 968159
- Report Number(s):
- LLNL-CONF-418136; TRN: US0904613
- Resource Relation:
- Conference: Presented at: American Physical Society Division of Plasma Physics 51st Annual Meeting, Atlanta, GA, United States, Nov 02 - Nov 06, 2009
- Country of Publication:
- United States
- Language:
- English
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