Wall reflection issues for optical diagnostics in fusion devices.

The problem of light reflection has been raised as a high priority issue for optical diagnostics in next step fusion devices where metallic wall environment will generate significant perturbations in the diagnostics measurements. Tore Supra is a large size tokamak equipped with water-cooled stainless-steel panels used to sustain the plasma long shot radiations. These panels are highly reflective and affect significantly optical systems.

Disturbance of laser-induced-fluorescence measurements of NO in methane-air flames containing chlorinated species by photochemical effects induced by 225-nm-laser excitation.

Laser-induced fluorescence measurements of NO in CH(4)-air flames seeded with CH(3)Cl and CH(2)Cl(2) are described. The measurements are perturbed by strong photochemical effects characterized by UV emissions. The contribution of these background emissions is taken into account on the basis of an on-line-off-line resonance procedure.

Experimental evidence of intermittent convection in the edge of magnetic confinement devices.

Probe measurements in the PISCES linear device indicate the presence of plasma radially far from where it is produced. We show that this is mainly caused by large-scale structures of plasma with high radial velocity. Data from the Tore Supra tokamak show striking similarities in the shape of these intermittent events as well as the fluctuation density probability distribution and frequency spectrum.

Internal transport barrier with ion-cyclotron-resonance minority heating on tore supra.

Recently, reversed magnetic shear operation was performed using only ion-cyclotron-resonance frequency minority heating (ICRH) during current ramp-up. A wide region of reversed magnetic shear has been obtained. For the first time, an electron internal transport barrier sustained by ICRH is observed, with a dramatical drop of density fluctuations.