Date of Award

Spring 1984

Document Type

Dissertation - Restricted

Degree Name

Doctor of Philosophy (PhD)


Electrical and Computer Engineering

First Advisor

Ishii, Thomas K.

Second Advisor

Heinen, James A.

Third Advisor

Sedivy, Jan K.


When a gas filled tube is exposed to Electromagnetic radiation, the gas contained in the tube is ionized if certain parameters exist. Such parameters are the applied electric field strength and frequency, gas type and pressure and tube shape and size. These parameters, acting together, define other parameters such as mean free path, characteristic diffusion rate, etc. If an external circuit is created by connecting the filaments of the tube with conducting wires, a pure Direct Current (D. C.) will flow in the circuit. The question to be answered in this work is how this D. C. is created and extracted. This investigation utilized an R. F. radio with an output voltage of 180 volts, peak-to-peak and a frequency of 4.25 x 10('6) Hz as a source of energy. The gas filled tubes used were conventional fluorescent tubes of two different lengths. The two antenna leads that emanated from the radio, which would conventionally be used as the Radiator lead and the Ground Plane lead, (Designated as R. F. Electrode #1 and R. F. Electrode #2, respectively) coupled energy into the fluorescent tube. Conducting rings were fashioned from household aluminum foil and fastened to the antenna leads. The rings were positioned around the glass envelope of the fluorescent tube. When the radio was activated, current flowed in the external circuit. The amount of current that flowed in the external circuit was found to be a function of the relative positions of R. F. Electrode #1 and R. F. Electrode #2 to themselves as well as to the external circuit electrodes. By investigating the literature and by experimenting with tubes of different lengths, it was resolved that R. F. Electrode #1 was the source of the plasma ionization. The ionization produced carrier populations of different constituents which traveled to the internal filaments of the tube at different speeds due to the difference in carrier mobilities. Because of the difference in migration speeds, mutual attraction of dissimilar constituents and repulsion of similar constituents, a sheath formed around the internal filaments of the tube. This sheath had a potential which was dependent on the relative position of the R. F. Electrode #1 which was the source of the ionization. When an external circuit was provided, current flowed as a consequence of the population gradient at the two external circuit electrodes.



Restricted Access Item

Having trouble?