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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:28 |
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Conference: Bucharest University Faculty of Physics 2004 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
Study of the electrical characteristics of a radiofrequency discharge in nitrogen at intermediate and high pressure
Authors:
R. Ionita, G. Vlad, I. Ciobanu, A. Lazea, G. Dinescu*
Affiliation:
National Institute for Laser, Plasma and Radiation Physics
PO Box MG 16-Magurele, Bucharest, 77125 Romania, *dinescug@infim.ro
E-mail
dinescug@infim.ro
Keywords:
radiofrequency discharge, electrical characteristics, high pressure discharge
Abstract:
Discharges at atmospheric, and over atmospheric pressures are of large interest for both practical (plasma treatments without use of the expensive vacuum pumps) and fundamental point of view (new phenomena in comparison to low pressure discharges). Using radiofrequency voltage supplies helps the operation of plasma sources at high pressure. The breakdown of a discharge is frequency dependent, showing a minimum in the radiofrequency domain, which is valid for a large range of pressures. This means that in comparison to DC discharges, the plasma will not only be easier to ignite, but to operate at lower current and power, presenting for the same pressure range, less risk for instabilities.
According to this interest a radiofrequency (RF) discharge (13.56 MHz) operated in nitrogen, used as the heart of a plasma jet based on parallel plate electrode configuration, was investigated from the electrical point of view. The current and voltage waveforms were recorded by a digital oscilloscope. By processing the waveforms the phase difference and the I-V characteristics were obtained.
The dependencies of the I-V characteristic and of phase difference upon pressure were studied. From these measurements the curves describing the onset of breakdown and of the filamentary discharge upon pressure were defined. The range of the pressure and of the power values for which the discharge operates in the glow regime was established.
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