Parametric amplification in a low-density plasma sheath.

Abstract

In this work we use the nonlinear properties of the sheath capacitance in a low-density plasma, whose purpose is to produce parametric amplification of a rf signal in the high-frequency band. The experiment has been carried out on the Linear Mirror Device LISA of the Universidade Federal Fluminense, where a helium plasma was produced using a radio-frequency source with a power that can be varied from 10 to 100 W. The experimental results show that it is practical to construct a parametric amplifier with high selective gain, which is very useful for the amplification of weak signals, where the gain factor and the relation between signal and noise are important. We find good agreement between the theoretical model proposed for the sheath capacitance and the experimental results.