Circular limiter H-mode plasmas in the Tokamak Fusion Test Reactor (TFTR)

Conference · Mon Jan 01 00:00:00 EST 1990

OSTI ID:6309769

Bush, C E

Circular limiter H-modes with centrally peaked density profiles have been obtained in TFTR using a highly conditioned graphite limiter. The transition to these centrally peaked H-modes takes place from the supershot to the H-mode rather than the usual L- to H-mode transition observed in other tokamaks. Bidirectional beam heating is required and the threshold power needed to induce the transition increases linearly with plasma current. Density peaking factors, n{sub e}(0)/{l angle}n{sub e}{r angle}, greater than 2.3 are obtained and, at the same time, the H-mode characteristics are similar to those of limiter H-modes on other tokamaks and the global confinement, {tau}{sub E}, can be >2.5 times L-mode scaling. Microwave scattering data from the edge plasma shows broad spectra at k = 5.5 cm{sup {minus}1} which begin at the drop in D{sub {alpha}} radiation and are strongly shifted in the electron diamagnetic drift direction. This implies a poloidal rotation, which begins at the transition to the H-mode, of {approximately}10{sup 4} m/sec. During an edge localized mode instability (ELM), these apparent rotations cease and Mirnov fluctuations in the 50--500 kHz range increase in intensity. Electron cyclotron emission data shows the origin of the ELMs and probably the transition layer to be located a few centimeters inside the plasma surface. A short review of requirements for controlled thermonuclear reactions is given in the introduction. 16 refs., 7 figs.

• Research Organization: Princeton Univ., NJ (USA). Plasma Physics Lab.
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6309769
• Report Number(s): CONF-9008171-2; ON: DE91005850; TRN: 91-001240
• Resource Relation: Conference: 2. Edward Bouchet international conference on physics and technology, Legon (Ghana), 14-17 Aug 1990
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
TFTR TOKAMAK
H-MODE PLASMA CONFINEMENT
DEUTERON REACTIONS
FLUCTUATIONS
LIMITERS
MAGNETIC FIELDS
PLASMA HEATING
TRITIUM TARGET
CHARGED-PARTICLE REACTIONS
CONFINEMENT
HEATING
NUCLEAR REACTIONS
PLASMA CONFINEMENT
TARGETS
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
VARIATIONS
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production