
317Experimental Setup for Basic Plasma Studies
the MC. From the radial variation of normalized wavelength in Figure 20.12,
it can be seen that the wavelengths decrease to very small values in these
annular windows, even below the cutoff wavelength, and thereby waves can
pass through the periphery of the central, overdense plasmas.
These narrow propagation windows in the MC periphery can be correlated
to the resonance phenomena in MW plasmas. A plot of UHR (
l
2
+
β
2
= 1) and
ECR (
β
2
= 1) resonances, as a function of the MC cross section, is shown in
Figure 20.13. The null line corresponds to resonance. The ECR (B
ECR
= 1072 G)
1