[en] Short communication

[en] Fast penetration of a magnetic field into a plasma junction of plasma switches is considered. The case n=const (n is the plasma density), when the conductor density has a sharp gradient at the plasma-electrode boundary and intensified diffusion of the magnetic field along the electrode occurs, is studied

[en] The density, drift velocity and reproducibility of the plasma produced by a cable plasma gun array have been measured with a charge collector array. The plasma is used to prefill a coaxial plasma-opening switch with a conducting time approaching 0.4 μs. The reproducibility of the plasma source in subsequent shots is better than 5%. Near the gun nozzle and the opposite electrode, the plasma density amounts to 10¹⁵ cm^-3, which is 2 times to 3 times that in the gap between the two coaxial electrodes. A plasma drift velocity of about 2.4 cm/μs is observed from the time of flight of the charged particles. Both plasma density and drift velocity increase almost linearly with the rise in charge voltage

[en] Positive polarity regime of microsecond plasma opening switch (MPOS) was investigated at the DOUBLE generator (480 kV, 300 kA, 1.3 μs). The measurements of the ion flow parameters showed the considerable enhancement of the ion current density over the thermal flow in the conduction phase. Ion losses reached more than 80% of the full energy losses in MPOS operating on the inductive load

[en] Assessment has been made of the problem of the on-resistance and temperature effects in the three power transistor combinations, such as Darlington-types or IGBT. The IGBT is a device in which the drain of the MOSFET feeds the bipolar base in monolithic (IC and Power on the same chip) to give it both the MOS and bipolar advantages. The high temperature operating characteristics of the device are discussed and compared to that of power bipolar transistor. Unlike the power bipolar transistor whose operating current density shows current crowding at above forward collector current of 4Amps and forward voltage drop above 0.4V, the IGBT is found to maintain its high current density above forward collector of current 1Amp (or a forward voltage drop above 1.2V). The results also indicate that these devices (IGBTs) can be interdigited (paralleled) without current hogging problems if the forward conduction occurs at forward voltage drops in excess of 1.2V, and this makes it the best candidate for automotive ignition power switches. (author). 20 refs, 10 figs, 1 tab

[en] The influence of an external magnetic field on the performance of a high-impedance plasma opening switch is studied experimentally. A 1.5-fold increase in the output voltage of a plasma opening switch operating in the erosion mode is achieved by applying an external magnetic field. The magnetic field strength and the parameters of the plasma opening switch at which the maximum output voltage is attained are determined. It is shown experimentally that the predicted dependence of the maximum output voltage on the Marx generator voltage, U_POS [MV] = 3.6 (U_MG [MV])^4sol7, is confirmed experimentally

[en] Considerable interest has recently been generated in a new type of high-voltage low-pressure switching device, often named the pseudospark switch. One of the problems for such switches is to increase the static breakdown voltage since this parameter is very important in itself and. besides, determines the ability for the switch to operate in high frequency mode. In parallel with other methods, a so-called blocking electrodes are used to solve the above problem. The action of the blocking electrodes, is related to suppression a prebreakdown current in the main gap of the switch. Additional results in support of the current suppression concept are presented here

[en] This paper relates to the recovery capacities of a triggered vacuum switch after the crossing of a 25-μs high-current pulse. The recovery time is less than 100 μs. The authors experiment with several electrodes with different gaps, and study the influence of an axial magnetic field on the switch

[en] It is known that a sudden creation of a plasma medium of plasma frequency ω_ρ splits a traveling wave of frequency ω_o into two new waves of frequencies. The negative value for the frequency here indicates a reflected wave. The effect of a sudden collapse of the plasma medium, on a travelling wave of frequency ω_o is shown to be the creation of two new waves of frequencies. A numerical solution is obtained for the case of a gradual collapse of the plasma medium. For the case of a slow decay of the particle density an approximate WKB type solution is obtained. Several results are presented

[en] A two-dimensional electromagnetic PIC particle simulation code in cylindrical mesh, with r- and z- coordinate dependence, has been simply introduced. The code is used to study penetration of the magnetic field in plasma of PEOS. For different boundary, the behaviors of magnetic field are found, the reasonable explanations are given by physical analysis