The optical thickness of the plasma is often insufficient to fully absorb the microwaves during heating at the second harmonic of the electron cyclotron frequency. An analysis of the experiments to the T-10 tokamak allows us to find the criteria for the full absorption, and to construct a canonical profile transport model for the full and partial absorptions of microwaves. The conditions to the equivalence of discharges in different tokamaks, and in a pair of tokamaks with the optimized W7-X stellarator are formulated. For equivalent discharges, calculations to the T-15MD tokamak under construction with the obtained model coincide with measurements of electron and ion temperatures in the W7-X over a wide range of plasma densities. The validated model is used to analyze future shots of T-15MD.

An investigation of lithium influx to plasma, radiation, transport, and its influence on plasma parameters is carried out using spectroscopy and transport modeling methods. The lithium source in the discharge of the T-10 tokamak is a moving Li-limiter based on a tungsten capillary-pore system (CPS). A strong dependence is found between the Li influx to plasma on the distance between the Li-limiter and plasma current boundary in the scrape-off layer (SOL) region. It is shown that if the Li-limiter is located on the radius of the chamber wall (r≈40 cm), lithium influx to plasma is at a low level with a value ∼2•10 18 s −1 and the Li nuclei concentration in the plasma does not exceed ∼0.5% of electron density n e with the effective charge value Z eff ≈1.2. If the Lilimiter is moved to the current radius (a L =30 cm), lithium influx to plasma reaches ∼3•10 20 s −1 , which leads to a formation of lithium plasma with the density limit of • » n 0.5 e Gw (the Greenwald density limit) with a Z eff value of ≈2.9 and ≈10% of the remaining deuteron density. In this case, the lithium radiation losses power estimated in Li-plasma is extremely low and does not exceed ≈15% of ohmic power. All obtained results are interpreted using transport models. Changing the lithization level of the chamber walls can significantly reduce the level of C, O, and W impurities and greatly affect the Z eff values. The dependencies of energy confinement times in the electron and ion components on the value of the averaged electron density are investigated in regimes with significantly varying Z eff values. The paper presents the computational analysis of the lithium radiation power at the plasma periphery and in the SOL as a function of boundary conditions, transport characteristics, and confinement times of lithium ions.

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