Abstract/Details

AN INVESTIGATION ON DIRECT CURRENT EXTRACTION FROM MICROWAVE INDUCED PLASMA


1981 1981

Other formats: Order a copy

Abstract (summary)

It has been found that if two metal electrodes are immersed in a microwave induced plasma, under certain conditions, a DC potential difference develops across the electrodes, and a DC current flows through a resistor externally connected to the electrodes. This phenomenon suggests a method of microwave-to-DC energy conversion.

Experimental investigations were made using mainly a commercial neon indicator lamp inserted into a waveguide and irradiated by a microwave signal of frequency 2.45 GHz. It was found that the magnitude of extracted current and its polarity could be changed by adjusting the impedance of the RF load of the lamp. Under optimal conditions, the lamp was ignited at about 0.5 W of incident microwave power, and 2 mA DC current into 500 Ohms DC load was obtained at 10 W of incident microwaves.

A theoretical model of the process consistent with the experimental data is proposed. It is based on the existence of a nonuniform microwave electric field distribution between extracting electrodes and the formation of unequal plasma sheaths around electrodes.

Numerical computation of the microwave electric field distribution for the particular structure of the NE-2 lamp is presented in the dissertation. The resultant field has been found to be highly nonuniform, and the position of its maximum has been determined to vary while adjusting the RF load reactance.

Such a nonuniform field produces a gaseous plasma characterized by an adequately nonuniform distribution of particle temperature and concentration. If the microwave electric fields at electrode surfaces are not equal, charged particles of the plasma diffuse toward the electrodes at different rates. This gives rise to different plasma sheaths around the electrodes, and when the external DC circuit is open, a difference in plasma sheath potentials appears across the electrodes. When the DC circuit is loaded, there is a flow of electrons through the external circuit from the high field electrode to the low field electrode. This process explains the origin of the extracted DC current. The value of the extracted current is determined by the microwave electric field distribution, geometry of the electrodes and discharge chamber, and properties of the gas used.

The conclusion of this work is that microwave-to-DC conversion by a microwave induced plasma is possible. Although the power handling capacity and the energy conversion efficiency of the NE-2 lamp and other laboratory-built structures were not satisfactory, some design criteria have been developed to improve both of them.

Indexing (details)


Subject
Electrical engineering
Classification
0544: Electrical engineering
Identifier / keyword
Applied sciences
Title
AN INVESTIGATION ON DIRECT CURRENT EXTRACTION FROM MICROWAVE INDUCED PLASMA
Author
LOPUCH, STANISLAW LEONARD
Number of pages
176
Publication year
1981
Degree date
1981
School code
0116
Source
DAI-B 42/12, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
University/institution
Marquette University
University location
United States -- Wisconsin
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
8211437
ProQuest document ID
303156160
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/303156160
Access the complete full text

You can get the full text of this document if it is part of your institution's ProQuest subscription.

Try one of the following:

  • Connect to ProQuest through your library network and search for the document from there.
  • Request the document from your library.
  • Go to the ProQuest login page and enter a ProQuest or My Research username / password.