N. V. Kuzmin

The TRT (Tokamak with Reactor Technologies) should be an important step in the implementation of the Russian national program of controlled thermonuclear fusion. The main task of the TRT facility is to obtain a long-term plasma pulse, which is possible only if superconducting coils are used. To control the parameters of thermonuclear plasma, it is necessary to develop and create an entire complex of diagnostic systems. One of the designed diagnostic systems for the TRT is the diagnostics of “active spectroscopy” (AS), referred to in the English literature by the abbreviation CXRS (Charge eXchange Recombination Spectroscopy). In an earlier publication [1] the possibility of creating this diagnostics was considered both on a heating and on a diagnostic beam of atoms, and it was shown that the diagnostics would work only using a diagnostic beam of atoms. At the same time, only the implementation of the observation system in the horizontal plane from the equatorial port of the TRT facility was considered. This paper presents the concept of a vertical observation system for the diagnostics of CXRS on the TRT facility. A vertical observation system is necessary to measure the poloidal rotational velocity at the edge of the plasma. The paper presents the results of modeling of light spectral profiles emitted by plasma and estimates of the levels of active and background signals, as well as the signal-to-noise ratio. A measurement scheme is proposed for simultaneous registration of emission over a minor radius from r = 0.8a to r = a. The optical system for collecting light from plasma is described, and a description of the proposed measuring equipment is given. The plasma parameters measurement accuracy and the achievable spatial resolution are estimated.

An improved prototype of the large-aperture, high-resolution spectrometer−polychromator (the so-called high-etendue spectrometer, HES) has been designed for spectroscopy diagnostics of plasma, in particular, for the Charge-eXchange Recombination Spectroscopy (CXRS) diagnostics at the ITER facility. Ion temperature profiles, poloidal and toroidal plasma rotation velocities, and low-Z impurity densities can be measured using the CXRS technique. The HES is equipped with novel, high-efficiency compact sCMOS cameras with low noise level, wide dynamic range, high quantum efficiency, and almost 100% working cycle. The HES is based on three transmission holographic gratings, which allow its simultaneous operation in three spectral bands: 468 ± 5, 529 ± 5, and 656 ± 6 nm. The main performance characteristics of the cameras, transmission gratings, and the spectrometer as a unit have been measured. It has been established that the characteristics of the developed HES satisfy the requirements for the spectroscopic equipment intended for measurements of the ITER CXRS diagnostic system.

Светосильный спектрометр-полихроматор высокого разрешения, оснащенный научными кмоп-камерами, для спектроскопической диагностики плазмы токамаков