A 'Relativistic Mirror' Experiment with Frequency Tuning and Energy Gain.
NAVAL RESEARCH LAB WASHINGTON D C
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The front of an intense relativistic electron beam has been used to reflect a counterstreaming electromagnetic wave fi sub i 9.3 GHz, Pi sub i 250 kW. A doubly-Doppler-shifted reflected wave with a pulse duration on the order of a nanosecond has been produced with a six-fold increase in frequency, a 13-dB power gain, and a doubling of wave energy. The output has been analyzed with a multi-channel grating spectrometer and found to have a spectral width Delta lambdalamda of approx. 5. The reflected-wave frequency was tunable over a range of approx. or - 20 by simply varying the external magnetic field, and over a much broader range by simultaneously changing the beam rise time. All these observations are in good agreement with a simple theoretical model of beam-front scattering. This mechanism represents a new kind of short-pulse, high-power, tunable source of millimeter and probably submillimeter wavelength radiation, and it could be immediately useful as an electron beam velocity diagnostic. Author
- Electricity and Magnetism
- Particle Accelerators
- Quantum Theory and Relativity