The paper deals with the main features of RF systems (P less than or equal to 5 MW, f less than or equal to 30 MHz) for ion-cyclotron heating of plasma on the TSP tokamak. The systems are based on the principle of self-excitation of oscillations in a complex distributed circuit, including resonant antennas and feeders, with a powerful RF triode as the only nonlinear element. Two circuit configurations are discussed: 2 MW/1(2) antenna and 5 MW/4 antennas. The concept and design of a compact modular resonant antenna with high density of radiated power (P/S less than or equal to 5 KW/cm(2)) are examined. Results of computer simulation of RF oscillatory circuit parameters are presented.

In this paper the ECR-system designed for plasma experiments on electron-cyclotron resonance heating on the T-15 facility is described. Its power is 12 MW, RF-wavelength 3.6 mm, operating pulse duration 1.5 s. The generator complex consists of 24 independently operating gyrotrons. RF-power from each unit is injected into the plasma from outboard side by means of combined waveguide and quasi-optical transmission components. The direction of RF-wave injection is perpendicular or at the angle with respect to the toroidal field. RF-generator magnet system (MS) comprises the main superconducting solenoid with the maximum field 5 T and two normal correcting coils. Power supply system of the whole complex and filament heating supply system with gyrotron emission current stabilization are also described. The system for gyrotron protection against the high voltage breakdowns limits the energy at the breakdown to not more than 10 J. The main principles of the automatic control system organization and of the device for RF-power control are presented.

An electron gun with a multipoint explosive-emission cathode is described that generates an electron beam of large cross section with a current density of approx. = 1 A/cm/sup 2/, an electron energy of greater than or equal to 10/sup 5/ eV, and a duration of greater than or greater than or equal to 10/sup -6/ sec. The supply system and design of the cathode unit allow prolonged operation of the electron gun with a pulse repetition frequency of up to 25 Hz.

A stable toroidal discharge in a TT-3 tokamak device was obtained in the region where the Kruskal-Shafranov criterion does not hold. (AIP)

It has been shown experimentally that 9<1 under certain conditions when radio-frequency (rf) modulation of the longitudinal magnetic field H/subz/ can provide stability of a plasma column with a quasiconstant current I against helical MHD perturbations. The limits of the stability regions have been determined. These limits agree with those found previously in experiments with rf modulation of the quasiconstant current, provided the relative modulation of the plasma radius, epsilon, is taken as a parameter. (AIP)