Radio-frequency-assisted current startup in the Fusion Engineering Device
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 Laboratory, Fusion Engineering Design Center, Oak Ridge, Tennessee
- OSTI ID:
- 5399145
- Journal Information:
- Fusion Technol.; (United States), Vol. 6:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Inductive current startup in large tokamaks with expanding minor radius and rf assist
Inductive current startup in large tokamaks with expanding minor radius and RF assist
Related Subjects
HIGH-FREQUENCY HEATING
RF SYSTEMS
TOKAMAK DEVICES
CHARGED-PARTICLE TRANSPORT
ECR HEATING
ELECTRIC CURRENTS
ELECTRONS
PARTICLE MODELS
PLASMA CONFINEMENT
PLASMA DRIFT
PLASMA EXPANSION
PLASMA SIMULATION
ROTATIONAL TRANSFORM
SENSITIVITY
START-UP
TIME DEPENDENCE
CLOSED PLASMA DEVICES
CONFINEMENT
CURRENTS
ELEMENTARY PARTICLES
EXPANSION
FERMIONS
HEATING
LEPTONS
MATHEMATICAL MODELS
PLASMA HEATING
RADIATION TRANSPORT
SIMULATION
THERMONUCLEAR DEVICES
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production
700205 - Fusion Power Plant Technology- Fuel
Heating
& Injection Systems