[en] The propagation characteristics of the beam under various initial conditions are investigated by means of PIC method. The influences of density modulation and velocity modulation on the propagation characteristics are discussed and compared. The results reveal that by changing the amplitude of the two kinds of modulations and the phase difference between them, the distribution property of the first harmonic of the current density can be adapted along the beam propagating path, which is a feasible method to enhance the beam-wave interaction efficiency in Cerenkov HPM devices

No abstract available

[en] The common characteristics of most capacitive energy storage systems are the use of gas switch, while the limitation of the recovery of gas switch and ablation of electrode lead to low repetition rates and short life. The widely researched technology of magnetic pulse compression has great perspective in long life, high average power and high repetition rates in the pulsed power system. Through the theoretical analysis and simulation of the parameters of the BOOST circuit, the LC circuit and magnetic compression circuit, the pulse generator circuit based on the BOOST circuit, the LC circuit, the pulsed transformer and the magnetic switch is designed, simulated and optimized by Pspice. The output pulse has 55 kV voltage and 500 ns pulse-width. (authors)

[en] An electron-beam transformer accelerator, which make up a primary store capacitor system, an air core spiral strip transformer, a water Blumlein line and a field-emission diode, is described. The experimental results show that the voltage of field-emission diode rises up to 420 kV, electron beam current is about 40 kA and the pulse length is more than 80 ns

[en] An electron-beam Tesla-transformer accelerator is described. It consists of the primary storage energy system. Tesla transformer, oil Blumlein pulse form line, and the vacuum diode. The experiments of initial stage showed that diode voltage rises up to about 500 kV with an input of 20 kV and the maximum electron-beam current is about 9 kA, the pulse width is about 50 ns. This device can operate stably and be set up easily

[en] A high efficient relativistic backward wave oscillator with coaxial nonuniform slow-wave structures (SWSs) and depth-tunable extractor is presented. The physical mechanism to increase the power efficiency is investigated theoretically and experimentally. It is shown that the nonuniform SWSs, the guiding magnetic field distribution, and the coaxial extractor depth play key roles in the enhancement of the beam-wave power conversion efficiency. The experimental results show that a 1.609 GHz, 2.3 GW microwave can be generated when the diode voltage is 890 kV and the beam current is 7.7 kA. The corresponding power efficiency reaches 33.6%.

[en] This paper discusses a small-sized H.V. nanosecond pulse generator which can produce a H.V. pulse with 120 kV amplitude, more than 5 kV/ns front gradient and 100 ns width. The generator has been used as a trigger to REB accelerator, the pulse resource of H.V. EMP simulator and the energy resource for studying discharge properties of different mediums, as well

[en] The fundamental mode frequency of a magnetically insulated transmission line oscillator is investigated theoretically by the equivalent circuit method, and an exact theoretical formula about the fundamental mode frequency is given. The theoretical results are compared with the simulation and experimental results, which shows that the relative error, which is calculated according to the theoretical and simulation frequencies, is less than 3%, so the validity of the theoretical formula is verified.

[en] This paper presents an improved X-band magnetically insulated transmission line oscillator (MILO) design that addresses several deficiencies found in previous experiments. In the new structure, an improved design of the launch point region is introduced, which improves the electric field uniformity on the cathode surface in order to suppress cathode flare formation. In addition, a new design for the load region is presented where the end of the cathode consists of four polymer velvet rings, a mesh is adopted as the anode of the load, and a metal barrel is employed as the beam dump. These improvements reduce energy deposition in the beam dump to less than 30 J/g, which probably suppresses plasma formation in the load region. Typical simulation results of the improved MILO show that when the applied voltage is 690 kV and beam current is 48 kA, high power microwave with an average power of 3.5 GW and a frequency of 9.26 GHz is generated. Furthermore, new meshes are specially studied for long pulse operation of this improved X-band MILO. Correlative experiments are being carried out in our laboratory.

[en] A compact capacitive divider with response time of 2.8 ns which is used to measure high voltage pulse, is built. It have been applied to measure high voltage pulse and resonant waves of Tesla-transformer-type electron beam accelerator