A new possibility of coherent microwave radiation by relativistic particles

Scientists are interested in the problem of high-power sharp-directed microwave radiation production. It is generally admitted that submillimeter and shorter-wave (up to light) range radiation may be produced by means of relativistic and ultrarelativistic electron beams provided that Doppler shift permits radiation wavelengths essentially smaller than generating system characteristic size. Undulator-based free electron lasers (FELs) are the most promising among the facilities of this type. It is shown that normally crossing constant or pulsed magnetic and electrical fields can provide the conditions needed to start radiation generation using the beams of already operating accelerators.<>