Sergei N. Tugarinov

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.

Data on the cross section and kinetic rate of charge exchange (CX) between the bare beryllium nucleus, the ion Be(+4) and the neutral hydrogen atom are of great interest for visible-range high-resolution spectroscopy in the ITER tokamak because beryllium is intended as the material for the first wall in the main chamber. Here an analysis of available data is presented, and the data needs are formulated. Besides the active probe signal produced by the CX of the diagnostic hydrogen neutral beam with impurity ions in plasma, a passive signal produced by the CX of impurity ions with cold edge plasma is also important, as it shows in observation data from the JET (Joint European Torus) tokamak with an ITER-like beryllium wall. Data in the range of a few eV/amu to ~100 eV/amu (amu stands for the atomic mass unit) needed for simulations of level populations for principal and orbital quantum numbers in the emitting beryllium ions Be(+3) can be obtained with the help of two-dimensional kinetic codes. The lack of literature data, especially for data resolved in orbital quantum numbers, has instigated us to make numerical calculations with the ARSENY code. A comparison of the results obtained for the one-centre Coulomb problem using an analytic approach and for the two-centre problem using numerical simulations is presented.