The linear theory of an electron cyclotron maser (ECM) operating at the fundamental is developed. A set of analytic expressions, valid for all TE cavity modes, is derived for the starting current and frequency detuning using the Vlasov-Maxwell equations in the weakly relativistic limit. These results are applicable for an arbitrary electron velocity distribution as well as any longitudinal dist...

A cyclotron-resonance maser (CRM) experiment is performed in a high-gradient magnetic field using a low-energy electron beam ( approximately 10 keV/1 A). The magnetic field exceeds 1.63 T, which corresponds to a 45-GHz cyclotron frequency. The CRM radiation output is observed in much lower frequencies, between 6.6 and 20 GHz only. This discrepancy is explained by the finite penetration depth of...

The theory of plasma emission and of electron cyclotron maser emission, and their applications to solar radio bursts and to Jupiter’s DAM and the Earth’s AKR are reviewed, emphasizing the early literature and problems that remain unresolved. It is pointed out that there are quantitative measures of coherence in radio astronomy that have yet to be explored either observationally or theoretically.

We investigate wave amplification through the Electron Cyclotron Maser mechanism. We derive a semianalytic approximation formula giving the frequencies at which the absorption coefficient is negative. The coefficients still need to be computed to obtain the largest, and therefore the dominant, coefficient.

In this Letter, we present theory and particle-in-cell simulations describing cyclotron radio emission from Earth's auroral region and similar phenomena in other astrophysical environments. In particular, we find that the radiation, generated by a down-going electron horseshoe distribution is due to a backward-wave cyclotron-maser emission process. The backward wave nature of the radiation cont...

Experimental results of the first efficient operation of a long pulse cyclotron autoresonance maser (CARM) oscillator are presented. Output power of 1.9 MW for a beam energy of 450 keV and current of 80 A, corresponding to an efficiency of 5.2%, has been measured at 27.8 GHz in the TE1 , mode of a Bragg resonator. The observed frequency of the CARM emission corresponds to a Doppler upshifted fr...