Observation of particle transport barriers in reverse shear plasmas on the Tokamak Fusion Test Reactor
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey08543 (United States)
Perturbative experiments on the Tokamak Fusion Test Reactor [Phys. Plasmas {bold 4}, 1736 (1997)] (TFTR) have investigated transport in reverse shear plasmas. On TFTR, reverse magnetic shear plasmas bifurcate into two states with different transport properties: reverse shear (RS) and enhanced reverse shear (ERS) with improved core confinement. Measurements of the 14 MeV t(d,n){alpha} neutrons and charge-exchange recombination radiation spectra are used to infer the trace tritium and helium profiles, respectively. The profile evolution indicate the formation of core particle transport barriers in ERS plasmas. The transport barrier is manifested by an order-of-magnitude reduction in the particle diffusivity (D{sub T},D{sub He}) and a smaller reduction in the pinch within the reverse shear region. The low diffusivities are consistent with neoclassical predictions. Furthermore, D{sub T} and D{sub He}{approx}{chi}{sub eff}, the effective thermal diffusivity. Although the measured coefficients imply no helium ash accumulation, the situation is uncertain in a reactor due to unknown {chi}{sub eff} scaling. {copyright} {ital 1998} {ital American Institute of Physics}
- OSTI ID:
- 627779
- Report Number(s):
- CONF-971103--
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 5; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Particle and energy transport studies on TFTR and implications for helium ash in future fusion devices
Internal Transport Barrier for Electrons in JT-60U Reversed Shear Discharges