A transmission line filled with fast switched periodic plasma as a wide-band frequency transformer

An adiabatic theory is first presented to show the enhancing effects of a periodic structure and a magnetic field on wave frequency-shifting process by rapidly produced plasma. A device having a cylindrical coaxial line configuration and featuring with a periodic cusp magnetic field is then constructed to study the theoretically predicted time-domain wave phenomena. The magnetic field is introduced by ring-shaped permanent magnets installed outside the outer cylinder of the coax in an arrangement with alternating polarities. A rapid discharge by a rectangular voltage pulse between the center conductor and the outer cylinder of the coax generates periodically distributed plasma inside the coax. As an x-band test wave is introduced to propagate through the line, it is shown that the wave frequency is shifted both upward and downward by suddenly created periodically distributed plasma. The effectiveness of the magnetic field (periodic as well as uniform distribution) on broadening the power spectra of frequency-shifted waves is demonstrated by comparing the spectra for the magnetized cases with that for the unmagnetized case.