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.
The free boundary stellarator equilibria are studied in the framework of averaged equations. The structure of external magnetic fields created by currents flowing inside the plasma column is analysed. In all cases considered the dipole component of the magnetic field (in agreement with previous investigations) can only be used to determine the volume averaged value of the parameter @ if the net toroidal current is known. For zero net current operation it is shown that the quadrupole component of the external magnetic field can be used for an estimate of the plasma pressure distribution, for example, in the framework of a one parametric set of profiles. The dependence of the external magnetic field on the current distribution for the given pressure profile is also investigated, and it is shown that there is a possibility of distinguishing at least strongly different current distributions (such as the peaked and offcentred current profiles considered here) either for a large shear system at high @ or for a device with averaged vertical elongation of the vacuum magnetic surfaces.
An approach to the integrated modelling of plasma regimes in the projected neutron source DEMO-FNS based on different codes is developed. The integrated modelling allows to eliminate uncertainties in external parameters for such tasks as plasma current ramp up, steady-state plasma consistency, plasma stability and heat load onto the wall and divertor plates. The following codes are employed for the integrated modelling. ASTRA transport code is used for adjustment of the steady-state regime parameters, NUBEAM Monte Carlo code for NBI incorporated into the ASTRA code, DINA free boundary equilibrium and evolution code, SPIDER free boundary equilibrium and equilibrium reconstruction code, KINX ideal MHD stability code, TOKAMEQ free boundary equilibrium code, edge and divertor plasma B2SOLPS5.2 code and Semi-analytic Hybrid Model (SHM) code for self-consistent description of the core, edge and divertor plasmas based on the experimental scaling laws. The consistent steady state regime for the DEMO-FNS plasma and the plasma current ramp up scenario are developed using the integrated modelling approach. Passive copper coils are considered for suppression of the instability to vertical displacement.
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