Electron-cyclotron current drive by radial transport of particles in the Continuous Current Tokamak

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:5021792

Park, Sanghyun

In the Continuous Current Tokamak at the UCLA, electron cyclotron current drive (ECCD) experiments have been conducted in the absence of ohmic heating or any other power input. With X-band source of 30 kW lasting 1 mS launched from the high field side in X-mode, 240 A of plasma current has been generated at the neutral pressure corresponding to the critical density for the wave frequency. The Spitzer resistivity calculated from the L/R decay time of the current yielded an electron temperature of 100 eV. For the interest of mapping out radial profiles of wave and particle parameters, S-band sources at 2.45 GHz, 1.5 kW lasting 8 mS with duty cycle of 50% have been used for quasi-steady state current drive experiments. There are four launching structures; (1) inside perpendicular, (2) outside perpendicular, (3) outside 60{degree}, and (4) outside {minus}60{degree} with respect to the toroidal magnetic field. It has been found that the four ways of microwaves give comparable results in plasma current driven. The plasma current measurements as a function of the radial location of the electron cyclotron resonance layer show a I{sub p}{approximately} {minus}sin({pi}r/a) where R{sub res} = R{sub 0} + r for {minus}a {ge} r {ge} O. The vertical field dependence has been shown to be I{sub p}{approximately}{minus}x exp({minus}x{sup 2}) where x is a normalized vertical field for {minus}{infinity} {lt} x {lt} {infinity}, indicating that the plasma current is reversed as the applied vertical field is reversed for all four launch schemes. As a toroidal electric field is applied, the co(counter)-injection with cos{sup {minus}1}({cflx k}{sub 0} {center dot} {cflx B}{sub t})=+({minus})60{degree} give the same result in plasma current driven. The energy distribution of the current carrying electrons as determined by the biased, two-side Langmuir probe show that the current is carried by the bulk of the plasma electrons whose energy is comparable to the plasma electron temperature.

• Research Organization: California Univ., Los Angeles, CA (United States)
• OSTI ID: 5021792
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
TOKAMAK DEVICES
CURRENT-DRIVE HEATING
CHARGE CARRIERS
ECR HEATING
ELECTRIC CONDUCTIVITY
ELECTRIC FIELDS
ELECTRON TEMPERATURE
ELECTRONS
FOKKER-PLANCK EQUATION
LANGMUIR PROBE
MICROWAVE RADIATION
CLOSED PLASMA DEVICES
DIFFERENTIAL EQUATIONS
ELECTRIC HEATING
ELECTRIC PROBES
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
HEATING
HIGH-FREQUENCY HEATING
JOULE HEATING
LEPTONS
PARTIAL DIFFERENTIAL EQUATIONS
PHYSICAL PROPERTIES
PLASMA HEATING
PROBES
RADIATIONS
RESISTANCE HEATING
THERMONUCLEAR DEVICES
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production