Parametric method of generation of low-frequency waves

We propose a new way to achieve parametric generation of low-frequency waves by electrons of magnetized plasma, which are accelerated under the conditions of electron cyclotron resonance (ECR). Low-frequency waves are excited using the diamagnetic effect that arises in the process of electron acceleratoin in the near-zone of various antennas under the ECR conditions, i.e., when the operating antenna frequency coincides with the local value of the electron cyclotron frequency and its harmonics. The amplitude modulation of the signal fed to the antenna is accompanied with a modulation in the diamagnetic effect and leads to radiation of waves into the background plasma at the modulation frequency. In this case, the extended plasma region that contains accelerated electrons acts as a parametric “bodiless” antenna. Basing on the results of experimental laboratory modeling performed on the large-scale KROT plasma setup, we propose a way to generate low-frequency whistler waves in the Earth's ionosphere by a high-power amplitude-modulated signal fed to the onboard antenna of a spacecraft. This research was supported by the Russian Foundation for Basic Research (Project No. 09-02-97058-r-povolzhye-a).

Diamagnetic perturbation as a function of the ratio of the pump pulse frequency to the electron cyclotron frequency near the antenna: resonance at the first and second ECR harmonics.
Low-frequency waves excited by amplitude-modulated high-frequency pumping under the ECR conditions and detected at various points over the radius of the KROT plasma column

Gushchin M.E., Korobkov S.V., Kostrov A.V., Odzerikho D.A., Priver S.E., and Strikovskii A.V. Parametric generation of low-frequency waves by plasma electrons accelerated under electron cyclotron resonance conditions // JETP Letters, 2010, V. 92, No. 2, P. 85–90.