Use of electron and proton beams for production of very low frequency and hydromagnetic emissions

The feasibility of using helical partical beams (∼10 kev, 1 A) fired from orbiting satellites to produce backward Doppler-shifted cyclotron emission (very low frequency from electrons, hydromagnetic or micropulsations from protons) is considered. It is found that the frequency and position of emission can be controlled by choice of particle energy and by gyrophase modulation (or 'rotation') of the beams at the desired frequency. Phase spread of the prephased beams through both natural processes and limitations of accelerators, as well as through radiative instability of the beams, should not be serious. Emitted powers of tens of watts are expected.