Current drive with fast waves, electron cyclotron waves, and neutral injection in the DIII-D tokamak
- General Atomics, San Diego, CA (United States)
- Lawrence Livermore National Lab., CA (United States)
- Massachusetts Inst. of Tech., Cambridge, MA (United States)
- Oak Ridge National Lab., TN (United States)
Current drive experiments have been performed on the DIII-D tokamak using fast waves, electron cyclotron waves, and neutral injection. Fast wave experiments were performed using a 4-strap antenna with 1 MW of power at 60 MHz. These experiments showed effective heating of electrons, with a global heating efficiency equivalent to that of neutral injection even when the single pass damping was calculated to be as small as 5%. The damping was probably due to the effect of multiple passes of the wave through the plasma. Fast wave current drive experiments were performed with a toroidally directional phasing of the antenna straps. Currents driven by fast wave current drive (FWCD) in the direction of the main plasma current of up to 100 kA were found, not including a calculated 40 kA of bootstrap current. Experiments with FWCD in the counter current direction showed little current drive. In both cases, changes in the sawtooth behavior and the internal inductance qualitatively support the measurement of FWCD. Experiments on electron cyclotron current drive have shown that 100 kA of current can be driven by 1 MW of power at 60 GHz. Calculations with a Fokker-Planck code show that electron cyclotron current drive (ECCD) can be well predicted when the effects of electron trapping and of the residual electric field are included. Experiments on driving current with neutral injection showed that effective current drive could be obtained and discharges with full current drive were demonstrated. Interestingly, all of these methods of current drive had about the same efficiency, 0.015 {times} 10{sup 20} MA/MW/m{sup 2}.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114; AC02-78ET51013; AC02-76CH03073; AC05-84OR21400
- OSTI ID:
- 6946433
- Report Number(s):
- GA-A-21003; CONF-920717-5; ON: DE93001359
- 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
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Related Subjects
DOUBLET-3 DEVICE
NON-INDUCTIVE CURRENT DRIVE
ANTENNAS
DAMPING
ECR HEATING
FOKKER-PLANCK EQUATION
NEUTRAL ATOM BEAM INJECTION
BEAM INJECTION
CLOSED PLASMA DEVICES
DIFFERENTIAL EQUATIONS
ELECTRICAL EQUIPMENT
EQUATIONS
EQUIPMENT
HEATING
HIGH-FREQUENCY HEATING
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA HEATING
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
700350* - Plasma Production
Heating
Current Drive
& Interactions- (1992-)