Radio-frequency-assisted current startup in the fusion engineering device
- Oak Ridge National Laboratory (ORNL)
- ORNL
- University of Michigan
Auxiliary radio-frequency (RF) heating of electrons before and during the current rise phase of a large tokamak, such as the Fusion Engineering Device (FED) (R{sub 0} = 4.8 m, a = 1.3 m, sigma = 1.6, B(R{sub 0}) = 3.62 T), is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation, 1 to 2 MW of electron cyclotron resonance heating power at about90 GHz is used to create a small volume of high conductivity plasma (T {sub e} approx. = 100 eV, n {sub e} approx. = 10{sup 19} m{sup -3}) near the upper hybrid resonance (UHR) region. This plasma conditioning, referred to as preheating, permits a small radius (a{sub 0} approx. = 0.2 to 0.4 m) current channel to be established with a relatively low initial loop voltage (less than or equal to 25 V as opposed to about 100 V without rf assist). During the subsequent plasma expansion and current rise phase, a combination of rf heating (up to 5 MW) and linear current ramping leads to a substantial savings in voltseconds by (a) minimizing the resistive flux consumption and (b) producing broad current density profiles. (With such broad profiles, the internal flux requirements are maintained at or near the flat profile limit.)
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1024766
- Journal Information:
- Fusion Technology, Vol. 6, Issue 1; ISSN 0748-1896
- Country of Publication:
- United States
- Language:
- English
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Inductive current startup in large tokamaks with expanding minor radius and rf assist
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Related Subjects
CHARGED-PARTICLE TRANSPORT
CLOSED PLASMA DEVICES
CURRENT DENSITY
ECR HEATING
ELECTRIC CURRENTS
ELEMENTARY PARTICLES
HEAT TREATMENTS
HEATING
HIGH-FREQUENCY HEATING
HYBRID RESONANCE
MATHEMATICAL MODELS
PARTICLE MODELS
PLASMA CONFINEMENT
PLASMA DRIFT
PLASMA EXPANSION
PLASMA HEATING
PLASMA SIMULATION
RADIATION TRANSPORT
RF SYSTEMS
ROTATIONAL TRANSFORM
THERMONUCLEAR DEVICES
TIME DEPENDENCE
TOKAMAK DEVICES