Fast wave ion cyclotron resonance heating experiments on the Alcator C tokamak

Technical Report · Thu Sep 01 04:00:00 EDT 1988

OSTI ID:6583430

Shepard, T D

Minority regime fast wave ICRF heating experiments have been conducted on the Alcator C tokamak at rf power levels sufficient to produce significant changes in plasma properties, and in particular to investigate the scaling to high density of the rf heating efficiency. Up to 450 kW of rf power at frequency f = 180 MHz, was injected into plasmas composed of deuterium majority and hydrogen minority ion species at magnetic field B/sub 0/ = 12 T, density 0.8 less than or equal to /bar n/sub e// less than or equal to 5 /times/ 10/sup 20/ m/sup -3/, ion temperature T/sub D/(0) /approximately/ 1 keV, electron temperature T/sub e/(0) /approximately/ 1.5--2.5 keV, and minority concentration 0.25 /approx lt/ /eta/sub H// less than or equal to 8%. Deuterium heating ..delta..T/sub D/(0) = 400 eV was observed at /bar n/sub e// = 1 /times/ 10/sup 20/ m/sup -3/, with smaller temperature increases at higher density. However, there was no significant change in electron temperature and the minority temperatures were insufficient to account for the launched rf power. Minority concentration scans indicated most efficient deuterium heating at the lowest possible concentration, in apparent contradiction with theory. Incremental heating /tau/sub inc// /equivalent to/ ..delta..W/..delta..P up to 5 ms was independent of density, in spite of theoretical predictions of favorable density scaling of rf absorption and in stark contrast to Ohmic confinement times /tau/sub E// /equivalent to/ W/P. After accounting for mode conversion and minority losses due to toroidal field ripple, unconfined orbits, asymmetric drag, neoclassical and sawtooth transport, and charge-exchange, it was found that the losses as well as the net power deposition on deuterium do scale very favorably with density. Nevertheless, when the net rf and Ohmic powers deposited on deuterium are compared, they are found to be equally efficient at heating the deuterium. 139 refs.

• Research Organization: Massachusetts Inst. of Tech., Cambridge (USA). Plasma Fusion Center
• DOE Contract Number: AC02-78ET51013
• OSTI ID: 6583430
• Report Number(s): DOE/ET/51013-256; PFC/RR-88-13; ON: DE89005035
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700108 -- Fusion Energy-- Plasma Research-- Wave Phenomena
ALCATOR DEVICE
ANTENNAS
CHARGE EXCHANGE
CLOSED PLASMA DEVICES
COLD PLASMA
CONFINEMENT TIME
DESIGN
DIFFERENTIAL EQUATIONS
ELECTRICAL EQUIPMENT
ELECTRON TEMPERATURE
EQUATIONS
EQUIPMENT
FOKKER-PLANCK EQUATION
HEATING
HIGH-FREQUENCY HEATING
HOT PLASMA
ICR HEATING
INHOMOGENEOUS PLASMA
ION TEMPERATURE
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA
PLASMA HEATING
PLASMA SIMULATION
PLASMA WAVES
SIMULATION
THERMONUCLEAR DEVICES
TOKAMAK DEVICES