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Empirical scaling laws (Goldston, Kaye-Goldston, ITER89P and ITER93H) for the confinement time τE in tokamaks depend on dimensionless global plasma parameters in a way which is difficult to associate with some general plasma physics model. It is shown that such dependences can arise from artefacts in the database used to derive the scaling expression. The artefacts involve inner relationships, for example, collinearities between variables. For the ITER L mode and H mode databases, it is shown that subsets of the scaling expressions are approximately constant. An alternative description of L mode, ELM-free, small ELM and giant ELM H mode data is given. The alternative description does not include the dependences upon plasma β, elongation and safety factor which are present in the above scaling laws; extrapolations to ITER parameters by this alternative data description are virtually the same as those by ITER89P and ITER93H. The alternative description is based on a simple electrostatic physics model (plateau scaling) in which confinement is degraded by non-collisional processes. It can describe global confinement data for all four confinement regimes; the common scaling features a multiplier C which is assigned a different value for each regime. The complex physics associated with MHD instabilities (ELMs, sawteeth, outer modes) is hidden in the multiplier C, and attempts are made to uncover such physics. In these attempts global confinement is made to scale with physics models rather than physics variables.

A dislocation model is proposed on the basis of the experimental data presented on the observed for the first time photorefractive effect in the DKDP crystal under the room temperature. It is shown, that similar effect can be expected in rather a wide class of crystalline materials with the well pronounced piezoelectric and electro-optic properties.

Photovoltaic current in high-temperature photorefractive DKDP crystal is measured directly using the original technique based on the current-to-voltage converter operating in the pulse regime. Theoretical consideration of the mechanisms involved and estimates of the observed values are presented. On the basis of the dislocation model we succeeded to get quantitative agreement with the existing experimental data in the value of photoinduced electrical field as well as in the dynamics ofboth the PR response and the photovoltaic current