Investigations on the time evolution of the plasma density in argon electron-beam plasma at intermediate pressure
The time evolution of the argon electron-beam plasma at intermediate pressure and low electron beam intensily was presented.By applying the amplitude modulation with the frequency of 20 Hz on the stable beam current,the plasma evolution was studied.A Faraday cup was used for the measurement of the e...
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Published in | Plasma science & technology Vol. 19; no. 3; pp. 47 - 53 |
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Main Author | |
Format | Journal Article |
Language | English |
Published |
01.03.2017
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Subjects | |
Online Access | Get full text |
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Summary: | The time evolution of the argon electron-beam plasma at intermediate pressure and low electron beam intensily was presented.By applying the amplitude modulation with the frequency of 20 Hz on the stable beam current,the plasma evolution was studied.A Faraday cup was used for the measurement of the electron beam current and a single electrostatic probe was used for the measurement of the ion current.Experimental results indicated that the ion current was in phase with the electron beam current in the pressure range from 200 Pa to 3000 Pa and in the beam current range lower than 20 mA,the residual density increased approximately linearly with the maximum density in the log-log plot and the fitting coefficient was irrelative to the pressure.And then three kinds of kinetic models were developed and the simulated results given by the kinetic model,without the consideration of the excited atoms,mostly approached to the experimental results.This indicated that the effect of the excited atoms on the plasma density can be ignored at intermediate pressure and low electron beam current intensity,which can greatly simplify the kinetic model.In the end.the decrease of the plasma density when the beam current was suddenly off was studied based on the simplified model and it was found that the decease characteristic at intermediate pressure was approximate to the one at high pressure at low electron beam intensity,which was in good accordance with the experimental results. |
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Bibliography: | Xiaoyan BAI 1,2, Chen CHEN 1, Hong LI1 and Wandong LIU 11 KTX Laboratory and Department of Modem Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China 2 State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Xi'an 710024, People's Republic of China The time evolution of the argon electron-beam plasma at intermediate pressure and low electron beam intensily was presented.By applying the amplitude modulation with the frequency of 20 Hz on the stable beam current,the plasma evolution was studied.A Faraday cup was used for the measurement of the electron beam current and a single electrostatic probe was used for the measurement of the ion current.Experimental results indicated that the ion current was in phase with the electron beam current in the pressure range from 200 Pa to 3000 Pa and in the beam current range lower than 20 mA,the residual density increased approximately linearly with the maximum density in the log-log plot and the fitting coefficient was irrelative to the pressure.And then three kinds of kinetic models were developed and the simulated results given by the kinetic model,without the consideration of the excited atoms,mostly approached to the experimental results.This indicated that the effect of the excited atoms on the plasma density can be ignored at intermediate pressure and low electron beam current intensity,which can greatly simplify the kinetic model.In the end.the decrease of the plasma density when the beam current was suddenly off was studied based on the simplified model and it was found that the decease characteristic at intermediate pressure was approximate to the one at high pressure at low electron beam intensity,which was in good accordance with the experimental results. 34-1187/TL electron-beam plasma, kinetic model, time evolution, residual density, phase lag |
ISSN: | 1009-0630 |
DOI: | 10.1088/2058-6272/19/3/035003 |