Introduction
The fundamental problem of nuclear fusion research based on magnetic confinement of a plasma of Deuterium and Tritium is the achievement of a high temperature (~100 Million deg. Kelvin) to allow the energy yielding fusion reactions to occur, and keeping the temperature for a sufficiently long "energy confinement time". The problem motivates the study of both experimental techniques and first principle theories to improve the operation regimes of tokamaks in view of an optimal design of the reactor-tokamak to be built by an international consortium, for the demonstration of net energy production from fusion.
Stream of research
In the context of the European Fusion Development Agency (EFDA) activities , the scientific staff of IFP/CNR has worked in 2003 on the Italian tokamak FTU(ENEA,Frascati), on the German ASDEX-U, on the Swiss TCV and French Tore-Supra and on the EU experiment JET-EFDA (the largest in the world) on the subject of the heat and particle transport using original techniques of measurement of heat diffusivity, based on injection of modulated electromagnetic wave (e.m.) power. The basic aim is the development of high confinement operation scenarios, that are required for burning plasma experiments.
The response of the tokamak plasma to localized high power pulses has allowed to test the existence of thresholds in the temperature gradient for the transition from "laminar" to turbulent heat diffusion regimes, and the associated characteristics of stiffness of the profiles, and a strong contribution has been given to the development and test of related theoretical models. Furthermore the response of the current profile and particle confinement to localized e.m. wave power has provided new data for comprehension of basic mechanism of tokamak plasma regimes. These studies confirm the great importance of the use of high power high frequency waves in tokamak experiments . Therefore the basic results obtained in 2003 are scientific and technical suitable to favor a qualified Italian participation to the next international development of a Fusion reactor.
Possible applications of the results of the research.
The experimental work has been planned, and carried out by the specilozed IFP staff on the facilities mentioned, within the wide opportunity of collaboration offered and supported by EFDA. In the case of the national experiment FTU IFP has also contributed over many years in manpower, in kind and financially to the building and running of the 1,2 MW electron cyclotron waves plant installed on the FTU tokamak , and used for these and other experiments.
The know-how of high power, high frequency wave technology is a precious asset with possible fallout in other branches of applied sciences as well as stimulating market of high technology industry.
Next step
Within the European EFDA activity the competence in the field of heat transport phenomena will keep a major role up to and during the Fusion reactor experiment. Therefore IFP will continue to participate to experiments of this kind on available tokamaks in a frame of international collaboration.
Financial support
During 2003 the total running cost of IFP scientific activity have been supported 75% by Euratom within the frame of the Euratom-ENEA-CNR Association, and 25% by CNR.
Focus