Inductive current startup in large tokamaks with expanding minor radius and rf assist

Technical Report · Wed Feb 01 00:00:00 EST 1984

DOI:https://doi.org/10.2172/5268165· OSTI ID:5268165

Borowski, S K

Auxiliary rf heating of electrons before and during the current-rise phase of a large tokamak, such as the Fusion Engineering Device (R = 4.8 m, a = 1.3 m, sigma = 1.6, B/sub T/ = 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 approx. 90 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 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 approx. 100 V without rf assist). During the subsequent plasma expansion and current ramp phase, a combination of rf heating (up to 5 MW) and current profile control leads to a substantial savings in volt-seconds by: (1) minimizing the resistive flux consumption; and (2) maintaining the internal flux at or near the flat profile limit.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5268165
• Report Number(s): ORNL/FEDC-83/8; ON: DE84006683
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CURRENT-DRIVE HEATING
TOKAMAK TYPE REACTORS
ECR HEATING
HIGH-FREQUENCY HEATING
MAGNETIC FLUX
MATHEMATICAL MODELS
START-UP
TRANSFORMERS
ELECTRIC HEATING
ELECTRICAL EQUIPMENT
EQUIPMENT
HEATING
JOULE HEATING
PLASMA HEATING
RESISTANCE HEATING
THERMONUCLEAR REACTORS
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production