Wide-range measurements of plasma density using a hairpin resonance microwave probe

Abstract

We propose a method for diagnostics of the density of weakly magnetized plasma using a resonance microwave probe, which allows decreasing the minimum measurable value of the density by three orders of magnitude, thus expanding the dynamic range of the measuring system significantly. Within the framework of this method, measurements are performed at a fixed frequency corresponding to the resonance frequency of a microwave probe in the absence of plasma, while minor variations in the resonance frequency of the system within the limits of the width of the inherent resonance are recorded by the method of amplitude-phase measurements. The paper presents a theoretical model of the measurement method and its experimental verification.