Frequency upshifting and pulse compression via underdense relativistic ionization fronts

Author

Savage, R.L., Jr. ; Brogle, R.P. ; Mori, W.B. ; Joshi, C.

Author_Institution

Dept. of Electr. Eng. & Phys., California Univ., Los Angeles, CA, USA

Volume

21

Issue

1

fYear

1993

fDate

2/1/1993 12:00:00 AM

Firstpage

5

Lastpage

19

Abstract

Theoretical and experimental work on the interaction of radiation with a relativistically propagating, underdense ionization front in a waveguide was performed. In the experiment 35-GHz microwave pulses were upshifted and compressed upon encountering a moving front. The frequency spectrum of the upshifted radiation was determined independently using sections of cutoff waveguides and a microwave diffraction grating. These frequency upshifts were proportional to the plasma density of the ionization front as predicted by the theory. The front density was determined using microwave interferometry. The pulsewidths of the upshifted radiation were measured with fast diode detectors. These pulsewidth measurements were also in good agreement with the theory. Frequency upshifts and pulse compressions of up to a factor of five were recorded in this experiment

Keywords

electromagnetic wave propagation in plasma; ionisation of gases; light propagation in plasma; plasma density; plasma diagnostics; plasma filled waveguides; relativistic plasmas; 35 GHz; cutoff waveguides; fast diode detectors; frequency spectrum; frequency upshifting; microwave diffraction grating; microwave interferometry; microwave pulses; plasma density; pulse compression; pulsewidths; underdense relativistic ionization fronts; upshifted radiation; Cutoff frequency; Diffraction gratings; Ionization; Ionizing radiation; Microwave propagation; Plasma density; Plasma measurements; Pulse compression methods; Pulse measurements; Waveguide theory;

fLanguage

English

Journal_Title

Plasma Science, IEEE Transactions on

Publisher

ieee

ISSN

0093-3813

Type

jour

DOI

10.1109/27.221097

Filename

221097