Speaker
Description
In future fusion power plants, the number of access points for measurements will be limited by the need to utilize a very large tritium breeding surface area on the tokamak walls. Therefore, it is necessary to develop innovative techniques to combine, ideally within a single compact diagnostic, several measurements of physical quantities useful for operation.
The frequency range spanning from the Far Infrared Radiation to the submillimeter region (100– 2000 GHz) has been historically used as a source of diagnostic information for important physical parameters in Nuclear Fusion Experiments. Amongst such parameters it can be cited plasma density, temperature, local magnetic field and fluctuations of all the above, using different types of diagnostics, based on the relevant physics principles.
TeraHertz – Time Domain Spectroscopy (THz – TDS) is a Spectroscopic technique that covers the same frequency range of the above diagnostics, by using pulsed, polarized electromagnetic waves. By translating this technique to the realm of nuclear fusion, a multifunctional diagnostic potentially capable of performing measurements akin to reflectometry, interferometry and polarimetry and in perspective ECE, can be realized.
WEST tokamak, thanks to its plasma parameters and long pulse length (up to twenty minutes), will be a very useful benchmark to test the capabilities of a THz-TDS diagnostic against the corresponding measurements of existing well-established systems.
In this presentation, the project for realization of a THz-TDS multifunctional diagnostic to be installed on WEST will be presented. The basic principles, the general layout, the technical solution devised and the analysis of the main expected issues will be discussed.