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As part of the creation of a unique T-15MD tokamak with a magnetic field of 2 T and an aspect ratio of 2.2, the first one of a series (8 pieces) of microwave setups of a megawatt power level for electron–cyclotron plasma heating and current drive was developed and successfully tested. The setup includes a gyrotron, power supplies, a microwave radiation transmission line, and a fast (response time is no more than 10 μs) gyrotron emergency protection system. The generation regime was experimentally demonstrated with the parameters 1 MW/30 s/82.6 GHz for an efficiency of 57%.

International audience; An up to 15 T pulsed magnetic field generator in a volume of a few cubic centimeters has been developed for experiments with magnetized laser plasma. The magnetic field is created by a pair of coils placed in a sealed reservoir with liquid nitrogen, installed in a vacuum chamber with a laser target. The bearing body provides the mechanical strength of the system both in the case of co-directional and oppositely connected coils. The configuration of the housing allows laser radiation to be introduced into the working area between the coils in a wide range of directions and focusing angles, place targets away from the symmetry axis of the magnetic system, and irradiate several targets simultaneously.

Gyrotrons for plasma fusion installations operated at frequencies 40–170 GHz with an output power up to 1 MW are presented. Some novel ideas are proposed to enhance gyrotron output energy, efficiency, frequency spectrum. In the collaboration between the Institute of Applied Physics and industrial company GYCOM Ltd the series of gyrotrons for plasma installations has been realized. The brightest examples are 170 GHz gyrotrons for ITER, long-pulse 140 GHz gyrotrons developed for EAST and KSTAR installations, 82.6 GHz for T-15MD tokamak, 28 GHz and 45 GHz complex for modern electron cyclotron resonance ion sources (ECRIS) facilities. Some steps were done in development of 230–700 GHz gyrotrons for future plasma installations and for plasma diagnostics.

We describe a series of gyrotron facilities developed at the Institute of Applied Physics of the Russian Academy of Sciences for studying physical processes during interaction of millimeter-wave electromagnetic radiation and matter. This paper presents the universal principle of designing such systems on the basis of a facility having an output radiation power of 5 kW at a frequency of 24 GHz. The main components of the facility and their technical parameters are described. Design of high-efficiency radiation sources and radiation transmission lines for various research applications is a sophisticated radiophysical problem, and the need for long-term stable operation with automatic adjustment of the parameters of the generation regime requires unique engineering solutions. Application of multimode electrodynamic devices in the radiation transmission line allows one to treat materials with significantly different dielectric properties, in particular, heat them up to temperatures of about (and exceeding) 2000°C. The vacuum-tight working chamber of the facility is a high-Q untuned cavity resonator having a volume of about 0.1 m3, in which microwave heating of items with characteristic dimensions of more than 10 cm can be performed. The automatic control system of the facility ensures its reliable and long-term failure-free operation.

A 45-GHz gyrotron-based microwave oscillator setup has been purposefully developed for powering of a superconducting electron cyclotron resonance (ECR) ion source. The setup provides a smoothly regulated output power in the 0.1–20-kW range (up to 26 kW in manual mode) with an efficiency of up to 50% and collector depression in both continuous wave (CW) and pulse modes. Pulse mode specifications: duration 5–200 ms, leading edge less than ${2}~\mu \text{s}$ , trailing edge less than ${1}~\mu \text{s}$ , repetition rate 1–10 Hz, and triggered operation using an external reference oscillator. The set of high-voltage power supplies (HVPSs) is equipped with a fast electronic protective system to ensure trouble-free operation of the gyrotron. The functional structure of the setup corresponds to the general design method for feedback-controlled microwave sources. The feedback loop consists of a power meter (or a detector unit, to the user’s choice), a control system, and an anode HVPS, the regulated voltage of which controls the output power of the gyrotron. The feedback characteristic time is less than 1 s. Feedback control is provided for both CW and pulse modes. The setup includes a unique quasi-optical line that transmits the microwave beam through a 2-m air gap, as well as a synthesized mode converter from the Gaussian beam to the TE01 or TE11 mode (to the user’s choice) installed on a 300-kV platform. During the tests, the developed setup proved to be a reliable and user-friendly tool applicable for long-term powering of the fourth-generation ECR ion sources.

The results of the development and experience of operation of a modernized charging system of the capacitor bank of the Iskra-5 laser facility are presented. The main performance characteristics of the devices that are included in the charging system are presented. A method for creating the hardware and software for the remote control and monitoring of the parameters of charging devices is described. The serviceability of the charging system during the operation of the facility is evaluated.

Problems in the development of high-voltage power sources (HVPSs), magnetrons and gyrotrons, providing powerful SHF devices of two types with a continuous generating mode of SHF and periodic-pulse radiation have been considered in this paper. High-voltage power sources (HVPS) are made on the basis of a transistor–capacitor direct-voltage converter. It ensures parametric stability and safety of the HVPS–powerful SHF device system in standard operating conditions and the emergency-operation mode due to HVPS’s negative external characteristic of this type. Mathematical models of an HVPS–powerful SHF device loop describing processes at the various output-voltage pulse-forming stages of HVPS’ have been proposed and checked. An HVPS–powerful SHF device system using the control-current injection method has been analyzed. A feedforward compensator the parameters of which are determined by confinement conditions in the given ranges of output regulation limits and dynamic parameters of forming pulses has been constructed using the asymptotic-expansion method of log-magnitude curves. Taking into account the results that have been obtained, a number of HVPS devices have been produced for technological and research SHF complexes. Basic technical specifications of two developed HVPS devices have been provided as an example in this paper. The first HVPS, which has a medium-voltage power of 60 kW (25 kV/2.4 A), enables generation by an SHF radiation gyrotron of up to 20 kW of capacity in both continuous- and periodic- pulse modes with a maximum frequency of 10 Hz. The second HVPS, which has a medium-voltage power of 20 kW (5 kV/4 A), is intended for supplying power to an M-168 magnetron in the periodic-pulse generation mode of SHF radiation with a maximum frequency of 500 Hz.

This paper describes gyrotron-based microwave generator setup developed by IAP RAS jointly with GYCOM Ltd. and intended for use in superconducting ECR ion source FECRAL (a Fourth generation ECR ion source with Advanced design in Lanzhou, China) [1, 2]. The setup is capable to provide output power up to 20 kW in both CW and pulse (5–200 ms duration with less than 1 μs fall time and up to 10 Hz repetition rate) operation modes with 45 GHz frequency. The system includes quasioptical transmission line and mode converter from the Gaussian beam to TE01 or HE11 mode (at the user's option).

Electromagnetic processes in high-voltage power supplies (HVPSs) based on a series resonant inverter are considered. It is shown that the analysis of a switching process in these devices should take into account the magnetizing inductance of the high-voltage transformer and capacitance of its windings. In order to decrease the dynamic losses in power semiconductor devices, the operating conditions were found and quantitative dependences between parameters of the HVPS were revealed by means of the developed HVPS mathematical model. The study results have been used in development of series of HVPSs for high-power electrophysical installations.

Amplifiers based on neodymium phosphate glass rods 60 — 100 mm in diameter are experimentally studied. The amplifiers are pumped by INP-16/250 tubular flash lamps placed in a universal pump cavity with a two-section mirror reflector. A compact high-voltage capacitive energy storage with a preionisation circuit was developed to supply the lamps.

A pulse magnetic-field generator producing pulse amplitudes up to 50 T with base durations of unities of milliseconds is described. The pulse magnetic field is obtained during discharging a capacitive storage through a thyristor-diode switch into a nitrogen-cooled solenoid. The repetition of the pulse amplitude of the current in the solenoid is ensured with an accuracy up to tenth of shares of a percent by stabilizing the precharge voltage of the storage and thermally stabling the solenoid. Using this generator, experiments for obtaining terahertz kilowatt-power radiation from 0.9- to 1.3-THz frequencies were successfully performed.

This paper presents a new thyristor-capacitor voltage regulator for a high-voltage pulse generator used in electrophysical installations based on different high-power vacuum electron devices. A thyristor-capacitor voltage regulator enables one to reduce the power intensity of storage capacitors that enter it. Expressions for calculating the parameters of components of the power supply are developed and results of simulation models of the power supply are reported.

Chargers of capacitive energy storages of electrophysical installations based on transistor-capacitor voltage converters are considered. Based on the developed procedure, electromagnetic and thermal processes in devices of this type are simulated. The results of investigations are used in the development of two chargers of capacitive energy storages of the megajoule range.

A new version of the relativistic backward wave oscillator (BWO) is proposed and investigated experimentally, where the cutoff (for the working mode mode) taper at the cathode end is replaced by a selective Bragg-type mode converter. In the experimental BWO model, which operates in the three-centimeter range and is equipped with a mode converter based on a slightly corrugated waveguide, a radiated power of 700 MW in pulses of duration up to 100 ns with an output spatial structure similar to a Gaussian wave beam is obtained at an accelerating potential of 0.8 MV and a focusing magnetic field of 7 kOe.

Results of elaboration of continuous-wave 258.6 GHz gyrotron with output power about 100 W with high stability of output parameters is presented. This paper includes results of calculation, design, experiments and technical requirements for main subsystems of gyrotron and auxiliaries. The gyrotron setup is a main part of a complex experimental system for NDP spectroscopy.

Second harmonic 24–28 GHz CW gyrotrons and series of gyrotron based setups for material processing and Electron Cyclotron Resonance Ion Sources (ECRIS) has been developed at IAP RAS. The possibility of significant output efficiency enhancement due to energy recovery for gyrotrons operating at cyclotron harmonic is demonstrated. The efficiency of 60% at 6 kW output power level at second harmonic 24 GHz gyrotron has been obtained by magnetic field profile optimization and single-stage energy recovery of the spent electron beam. It is shown, that the energy to sintering process can be significantly reduced (1.5–2 times) by simultaneous control of gyrotron voltage and solenoid current. Different varieties of broadband frequency gyro devices — multi-frequency or fast-swept in time operation — are under investigation for ECRIS. The double-frequency CW 10 kW second harmonic gyrotron with 2% fast frequency and a frequency-tunable gyro-BWO operating at center frequency of 60 GHz with CW output power about 10 kW are presented.

Summary form only given. The ISKRA-6 laser is a 128-beam, flashlamp-driven neodymium-glass laser that will produce near 0.6 MJ of light on target. Each of the 128 beams of the ISKRA-6 laser is amplified in two four-pass laser amplifiers. Pumping system of these amplifiers is consisted the 5120 xenon flash lamps that are drove by a power conditioning system. ISKRA-6 power conditioning system (PCS) is based on the capacitor storage bank to deliver approximately 35 k.F to each of 5120 flashlamps. So, PCS will be capable of storing nearly 215 MJ of electrical energy at 24 kV The capacitor bank will include the 256 unified modules. This paper describes the design of module and results of testing of module prototype. It also discusses the components of module including self-healing capacitors, main semiconductor closing switches based on reverse switched dynistors, and other components.

Summary form only given. A new generation of semiconductor closing switches based on reverse switched dynistors (RSD) has been developed to switch high-power current pulses with microsecond duration. In this report the results of theoretical and experimental investigations of RSD at peak current more than 500 kA and pulse duration up to 500 mus (at 0.1 Imax) are observed. The criteria of extreme peak current for switch taking into consideration the longtime performance under pulse-periodical mode are gave. The design and test results for switch under single pulse mode at operating voltage up to 25 kV and peak current up to 300 kA are described. The possibility of using such a switch in the ISKRA-6 capacitor bank is estimated.

The parameters of a pulsed microwave discharge in a 2.45 GHz chemical vapour deposition (CVD) reactor used for diamond growth are studied. It is shown that the use of the pulsed-wave mode allows one to increase the growth rate of polycrystalline diamond films by 2–3 times without deterioration of their quality for a fixed mean microwave power and a specified deposition area. An optimal pulse repetition rate is found, at which both the growth rate and the diamond film quality are higher than at the other repetition rates (for an equal mean power). We explain this effect by the increase in the near-surface atomic hydrogen density. The optimal pulse repetition rate value depends on the growth parameters (reactor geometry, gas pressure and power density), and on the growth substrate size. For the substrates 20–40 mm in diameter (and the CVD reactor used in the study), the optimal pulse repetition rate is 250 Hz. The method of graphite sample etching in hydrogen plasmas was used to measure the atomic hydrogen near-surface density. This method can be applied to the optimization of diamond film growth in CVD reactors of different types. Additionally, it can be used to compare different CVD reactors by determining the yield of atomic hydrogen. It is shown that at an equal mean power absorbed in the discharge, the maximum gas temperature during the microwave pulse increases, as the pulse repetition rate decreases. This behaviour of gas temperature can explain the similar dependence of the period-averaged intensity of the C2 radical optical emission (516.5 nm) on the pulse repetition rate.

A 24 GHz 3 kW CW gyrotron (n=2) with permanent magnet and microwave source based on the gyrotron are developed. The source incorporating a set of power supplies, transmission line, and PC-based RF power control extends a line of gyrotron systems designed as a versatile and user friendly tool for research in microwave energy applications.