No abstract

The phenomenon of plasma self-organization in a free-localized high-pressure microwave discharge has been investigated on the basis of the mechanism of ionization-field (IF) instability. Linear and weakly nonlinear stages of discharge evolution have been studied. It has been shown that IF instability at the nonlinear stage, due to the interaction of the harmonics with different wavevectors, can lead to the formation of a rich spectrum of plasma structures, from simple plane plasma autowaves to various 3D spatial structures (helical filaments and three-dimensional Bernard cells).

The most common control system for a synchronous motor with permanent magnets is a vector control system. The construction of such a system has a number of difficulties, one of them is the need to have information about the current position of the rotor. Data on the position of the rotor can be obtained using sensors, or include a supervisor in the control system. The article describes an adaptive observer of the position and speed of the rotor of a synchronous motor with permanent magnets. This observer is used in the system of sensorless vector control of the electric drive. The presented version of the observer of the engine state is realized by creating a model in the Matlab Simulink software package. The results of experimental verification of the presented observer at the stand with the use of an engine with a power of 200 W are shown. The aim of the work is to develop an observer that is stable to changing drive parameters. This is achieved by using a relay unit in the view of the observer, which implements the slip mode.

In this paper the possibility of operation of a high-power RF-RF hybrid plasma torch for materials processing is shown with help of numerical simulation. That kind of plasma torch consists of two coaxial ICP/RF torches connected in series. A mathematical model is presented which includes assumptions, basic equations, a computational domain with main sizes. The results of the calculation i.e. the temperature distributions inside the plasma torch for two modes of operation are shown. In the first mode the power is fed only to the first plasma torch (P 1=40 kW, P 2=0), in the second mode the both parts of the RF-RF hybrid plasma torch (P1 = 40 kW, P2 = 600 kW) operate. The obtained results can serve as a basis for further analysis of the operation of a high-power RF-RF hybrid plasma torch.