Experimental study of frequency shift of an electromagnetic wave propagating through a rapidly created periodic plasma

Summary form only given, as follows. Conversion of a monochromatic CW microwave into a frequency up-shifted and chirped pulse through its interaction with a rapidly created plasma has received considerable attention recently. The present work attempts to improve upon the results obtained by our group´s previous frequency shift experiments. The latest experiment replaces the previously studied single plasma layer in our vacuum chamber by a periodic discharge, obtained by placing Plexiglas strips across the conductors. These strips selectively prevent gas breakdown when a Marx capacitor bank is discharged between the electrodes. By properly arranging the Plexiglas strips, we can force the plasma to be rapidly created in a periodic structure. Numerical simulations lead us to believe that by proper selection of the periodic structure´s spacing and periodicity we can exercise some control over the spectral characteristics of the resulting broadband frequency shifted and chirped pulse train. We present a detailed description of the experiment, as well as comparisons between the simulation and experiment.