scholarly journals EXCITATION OF PLASMA BY ELECTRIC PULSES IN NEON MEDIUM

2019 ◽  
pp. 203-206
Author(s):  
D.Yu. Zaleskyi ◽  
G.A. Krivonosov ◽  
G.V. Sotnikov

We studied characteristics of the neon plasma source excited in the atmosphere under the following conditions: gas pressure is about 2 Torr, rectangular pulses have an amplitude from 200 to 800 V, pulse duration is from 0.2 to 10 μs, repetition rate is from 0.2 up to 1 kHz. There is a mode with a stable and unstable mode of existence of the plasma when the voltage on the electrodes of the plasma source varies from 800 to 350 V and from 350 to 250 V before the extinction of the plasma. The pulse from the PMT output in a steady state plasma has a decay of about 100 μs, the duration of which does not depend on the magnitude of the voltage, frequency and pulse duration. With a decrease in the supply voltage U, the pulse front duration with a photomultiplier is increased from 74 to 450 ns. It is shown that a large neon plasma relaxation time of 100 µs compared with a beam pulse duration of 1…2 µs allows only one time to change the phase of the accelerating field.

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Ivan A. Ivanov ◽  
V. O. Ustyuzhanin ◽  
A. V. Sudnikov ◽  
A. Inzhevatkina

A plasma gun for forming a plasma stream in the open magnetic mirror trap with additional helicoidal field SMOLA is described. The plasma gun is an axisymmetric system with a planar circular hot cathode based on lanthanum hexaboride and a hollow copper anode. The two planar coils are located around the plasma source and create a magnetic field of up to 200 mT. The magnetic field forms the magnetron configuration of the discharge and provides a radial electric insulation. The source typically operates with a discharge current of up to 350 A in hydrogen. Plasma parameters in the SMOLA device are Ti ~ 5 eV, Te ~ 5–40 eV and ni ~ (0.1–1)  × 1019 m−3. Helium plasma can also be created. The plasma properties depend on the whole group of initial technical parameters: the cathode temperature, the feeding gas flow, the anode-cathode supply voltage and the magnitude of the cathode magnetic insulation.


2009 ◽  
Vol 18 (03) ◽  
pp. 487-495 ◽  
Author(s):  
VINCENZO STORNELLI ◽  
GIUSEPPE FERRI ◽  
KING PACE

This work presents a single chip integrated pulse generator-modulator to be utilized in a short range wireless radio sensors remote control applications. The circuit, which can generate single pulses, modulated in BPSK, OOK, PAM, and also PPM, has been developed in a standard CMOS technology (AMS 0.35 μm). Typical pulse duration is about 1 ns while pulse repetition frequency is until 200 MHz (5 ns "chip" time). The operating supply voltage is ± 2.5 V, while the whole power consumption is about 15 mW. Post-layout parametric and corner analyses have confirmed the theoretical expectations.


Author(s):  
Waleed Khalid Shakir Al-Jubori ◽  
Yasir Abdulhafedh Ahmed

Study and analysis the effect of variable applied voltage on SCIM performances based on FEA is presented. Three phase squirrel cage induction motor SCIM has been investigated and numerically simulated using finite element method (FEM) with the aid of ANSYS software (RMxprt and Maxwell 2D/3D). This research presents study and analysis of the effects of the voltage variation on performance and efficiency of the three-phase induction motor of the squirrel cage type. The Finite Elements Analysis Method FEA is used as one of the best methods for analysis and simulation of electrical motors in addition to the possibility of dealing with nonlinear equations, Since the induction motor is a complex electromagnetic reaction, the researchers used the ANSYS program to represent and analyze the performance of the motor under variable supply voltage. The case studied in this research is three phases, 380V, 50Hz, 2.2kW, induction motor that widely use in industrial application. The aim of this research is to study the effect of voltage variation on efficiency, current value, power factor and torque of SCIM.  The RMxprt software has been used for modeling and simulating the induction motor and calculating the values of phases currents, input and output power in additional of overall efficiency at steady state condition. The next stage of the research is creating Maxwell 2-D design from the base model of RMxprt software, Maxwell 2-D model has the ability to computing the distribution of magnetic field and explaining the performance under steady-state operation. The obtained results show significant reduction of motor performance due to the effect of variation of apply voltage.


2019 ◽  
Vol 97 (2) ◽  
pp. 210-215
Author(s):  
C.V. Maridevarmath ◽  
G.H. Malimath

In the present work, the study of variation of relaxation time (τ) with viscosity of the medium (η) is carried out on four polar samples: 2-Nitroaniline, 4-Bromoaniline, 4-Chloroaniline, 4-Chlorophenol, and also on the binary mixture of 2-Nitroaniline + 4-Bromoaniline at room temperature by using microwave bench operating at a frequency of 9.59 GHz. In this regard, the different parameters like dielectric constant ([Formula: see text]), dielectric loss ([Formula: see text]), relaxation time (τs), macroscopic steady state viscosity (ηs), dynamic viscosity (ηd), and viscoelastic relaxation time (τve) were determined for all the systems. It is observed that the relaxation time (τs) increases with the increase in the viscosity of the medium for all the systems. Plots of log(τs) versus log(ηs) for all the systems show that variation of relaxation time is found to be nonlinear in the higher viscosity regions. This suggests the failure of Debye’s theory at these regions. Further, the nonlinear behaviour of relaxation time with the viscosity is explained by using the viscoelastic model suggested by Barlow et al. (Proc. R. Soc. A 309, 473 (1969). doi: 10.1098/rspa.1969.0053 ). It is also observed that macroscopic steady state viscosity (ηs) values are greater than the dynamic viscosity (ηd), and viscoelastic relaxation time (τve) values were found to be lower compared to the relaxation time (τs). These results suggest that the effective frictional resistance experienced by the molecules during reorientation is lower and the measured values of macroscopic steady state viscosity (ηs) are frequency dependent.


1989 ◽  
Vol 49 (3) ◽  
pp. 239-244 ◽  
Author(s):  
S. Szatm�ri ◽  
G. K�hnle ◽  
J. Jasny ◽  
F. P. Sch�fer

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