GAS DISCHARGE IN PLASMA-METAL WAVEGUIDE WITH VARYING RADIUS OF METAL ENCLOSURE PARTIALLY FILLED BY RADIALLY NON-UNIFORM MAGNETIZED PLASMA

The article presents the results of theoretical study of phase and attenuation characteristics of the symmetric electromagnetic wave in long waveguide structure that partially filled by radially non-uniform plasma immersed in external steady magnetic field. The results of theoretical study of stationary gas discharge sustained by this wave in the considered waveguide structure with slightly varying radius of metal enclosure in the framework of electrodynamic model are presented as well. It was studied the influence of the effective plasma collision frequency on the phase and attenuation wave properties and on the plasma density axial distribution in gas discharge considered for different radial plasma density profiles.

Trapped field characteristics of an HTS magnet with two holes using four magnetization methods

High temperature superconducting (HTS) magnets have widespread applications in a strong and steady magnetic field at low temperature. However, they can not be operated in persistent current mode (PCM) due to their immature joint technique without resistance. In order to realize the PCM, an HTS magnet stacked by double-hole rectangular HTS plates was proposed and fabricated. The trapped field of the HTS magnet was measured and simulated under four kinds of magnetization methods, field cooling (FC), zero field cooling (ZFC) and inner magnetization (a solenoid is placed at right/left hole of double-hole rectangular HTS magnet to magnetize HTS magnet) as well as combination of both methods. Meanwhile, the H-formulation is applied to the 3D model to analyze the electromagnetic behaviour. It was found that the trapped field of double-hole rectangular HTS magnet magnetized by FC with inner magnetization or ZFC with inner magnetization is higher than pure FC or ZFC magnetization. In inner magnetization, the trapped field of one hole in HTS magnet has no effect on the other one. In addition, the experiment results are in good agreement with numerical analysis, which can provide significant references for the magnetization method.

Application of Chinese Yin-Yang principle in the teaching of ‘electromagnetic fields and waves’

‘Electromagnetic Fields and Waves’ is an important professional basic course for students in the major of electrical and electronic engineering. Students regard it as the most difficult course because of numerous concepts and equations. Philosophy could assist the students’ understanding of the electromagnetic theories. The Chinese Yin- Yang principle reveals the basic composition and operating principles of the universe from the macroscopic and microscopic view, which provides another way to illustrate the electromagnetic phenomenon and equations. This paper presents a heuristic teaching practice carried out by combining the Chinese Yin- Yang principle and modern electromagnetic theory. Several lectures on vector analysis, electrostatic field, steady magnetic field, time-varying electromagnetic field, and gravitational field, even relativity and particle theories are given to show the application of the Yin- Yang principle. Student survey and exam results show that the adoption of Yin-Yang principle could help students to acquire the basic concepts in limited teaching hours and to promote philosophical thinking embodied in China's university education.