Kurchatov Institute is upgrading now the T-15 tokamak to the machine with D-shaped plasma and copper magnetic system, capable for realizing lower and upper single-null and double-null magnetic configurations. The heating and current drive (CD) system consisting of the neutral beam injection (NBI), electron cyclotron resonance heating (ECRH/CD), electron Bernstein waves (EBW) heating and CD, ion cyclotron resonance heating (ICRH/CD), helicon and Lower Hybrid (LH) waves heating and CD is aiming to provide an effective heating of both electrons and ions, and on- and off-axis CD. The main research topics foreseen are the features of the confinement at high magnetic field and low aspect ratio, Advanced Tokamak regimes, steady-state operation, effects of turbulence with an emphasis on the role of the radial electric field Er, Geodesic Acoustic Modes (GAM) and Zonal Flows (ZF) in transport and confinement (including plasma self-organization, profile resiliency, influence of the q-profile), investigations of MHD effects and disruptions, Alfven Eigenmodes (AE) and fast particles. Extended set of advanced diagnostics with identical equipment located at two toroidal positions will contribute to the 3D reconstruction of various types of the plasma structures like quasicoherent modes and long-range correlations. (C) 2015 Elsevier B.V. All rights reserved.

Electrodeless discharges can be employed to produce thermonuclear reactions providing that one is able to heat a long-lived stable plasma column to the required temperature. Some possible stability conditions have been derived theoretically. In addition experimental studies of discharges in chambers containing electrodes» 3 and also of electrodeless discharges • in toroidal chambers' » e have been performed with the purpose of solving these problems. It seems quite natural to attempt to heat the plasma by Joule heating as at first glance this possibility appears to be simplest and easiest, at any rate during the first stage of formation of a plasma possessing a high concentration of charged particles. Some results of investigations of electrodeless discharges in deuterium are reported in the present paper. The experiments were carried out with tubes of various dimensions under conditions involving a great variety of discharge parameters.

The plans of upgrading the superconducting tokamak T-15 and the program of physics and technology research for the period from 2008 to 2022 are outlined. The technical modernization of the T-15 is aimed at formation of the elongated divertor configuration, increase of the plasma discharge duration up to 1000 s and the total heating power to 20 MW. Upgrade will allow fusion oriented research on the T-15 supporting the ITER and DEMO projects.

The basic problems of Tokamak-15 electromagnetic system (EMS) elaboration are discussed. The EMS design is described, its main component parameters and features are presented. The R and D program for the EMS design including its most complicated component, the superconducting toroidal field system (TF system), is considered. Post-assembly EMS tests comprising the achievement of a toroidal field nominal value and plasma discharges are described.

In this paper the main objectives and research programme of T-15 are given: producing and investigation of the plasma with reactor-relevant parameters sufficient for reliable extrapolation to ignited plasma; testing of the engineering and technology, appropriate for a fusion tokamak reactor, on the operating device. The basie features of the facility are described and T-15 research programme is presented.

Results of the experiments on cooling, cryostatting, current tests and on Ohmic plasma heating at T-15 facility using the largest (at present) superconducting magnetic system with the current-carrying element based on Nb3Sn are given in the paper.

The current capacity tests of the T-15 toroidal coil assembly, which uses Nb3Sn, were carried out during February, 1990. The nominal current 3.9kA per turn was achieved with a winding temperature of about 7K. This current corresponds to a field at the axis of 3.5 T, and a field at the coil of 6.6T with a stored energy 380MJ.

Experiments on ECR heating of the plasma in the T-10 tokamak are reported. The gyrotron complex consisted of 11 source tubes with two distinct wavelengths, which made it possible to alter the profile of the heating power. The total power of the gyrotrons was varied up to 4 MW, which is nearly twice the level in previous experiments. This power increase made it possible to heat the electrons to a temperature T/sub e/(0) = 9 keV, which is comparable to what would be required for a reactor. At a heating power ten times the ohmic power, a refinement was made in the expression found previously for the global confinement time as a function of the power: tau/sub E/approx.P/sup -0.55//sub tot/. No significant deviations of the electron distribution from a Maxwellian distribution were observed at specific heating power levels up to 10 W/cm/sup 3/. Experiments carried out with various heating-power profiles showed that the conventional understanding of the electron transport, which determines the local thermal conductivities, is imcomplete. The electron transport depends on the heating-power profile in such a way that the plasma tends to retain ''canonical'' pressure and current-density profiles in the course of the heating. Calculations carried out onmore » the basis of a model of electron transport incorporating this tendency toward the retention of canonical profiles in the plasma lead to a completely satisfactory agreement with experimental data over the region of parameter values studied in the T-10.« less

An experimental study of the plasma during ohmic heating in the T-10 tokamak is reported. A stainless steel limiter was used, and the walls of the vacuum chamber were cleaned by a method aimed at effective removal of light impurities (carbon and oxygen). The data are compared with experimental data for limiters of other materials and with calculated results. The number of stable discharges is increased, but radiative losses continue to play a dominant role in the plasma energy balance.