QUASI-LINEAR TRANSPORT INFERRED FROM DENSITY FLUCTUATION SPECTRA

Expressions for the quasi-linear electrostatic electron particle and heat fluxes are derived in the wave frequency and electron collisionality regimes appropriate to the interior of the TEXT tokamak. These are expressed in terms of moments of the density fluctuation spectrum accounting for poloidal plasma rotation. Minimal assumptions are made as to the origin of the turbulence. The fluxes are then evaluated for an appropriate discharge condition on TEXT, using the density fluctuation frequency spectrum and equilibrium plasma potential measured by a heavy ion beam probe (HIBP). These are compared with the experimental fluxes for two measurements of the normalized rms poloidal wave number k-theta,rms-rho-s. For k-theta,rms-rho-s almost-equal-to 0.1, which is an upper bound of the HIBP two-point phase shift measurements, the electrostatic fluxes are negligible and the rms frequency of the fluctuations is much larger than the Doppler shifted electron diamagnetic drift frequency. However, for k-theta,rms-rho-s almost-equal-to 0.3, as supported by far-infrared (FIR) scattering and as expected for drift waves, the electrostatic fluxes are sufficient to account for the observed fluxes in the region of low collisionality. In addition, the rms frequency (consistent with FIR scattering) agrees with the Doppler shifted electron diamagnetic drift frequency. However, the computed fluxes fall increasingly short of the observed fluxes with increasing radius.