Fig. 4

Dependence of sensor impedance on plasma frequency for \(\omega _{\text{pe}}/\Omega _{\text{ce}} = 2.58\), 2.90, and 3.23 with \(\theta =90^\circ\). In panel a of the figure, the real component of the sensor impedance is depicted on the left-hand side, whereas panel b illustrates the imaginary component on the right-hand side. The vertical dotted lines represent the UHR frequency corresponding to each case