We used wavelet power spectra for an analysis of time series collected in selected points along the waveguide at different distances (optional) from the initial perturbation point. These power spectra are based on the wavelet analysis technique (Torrence & Compo, 1998) with the Morlet mother function with the parameter omega = 6.

The wavelet power spectra where both the cone of influence (COI, edge effects become important due to finite-length time series) and the confidence level (CL) relative to red noise are taken into account. In each time series, only the regions outside the COI with CL above 99% are considered significant. Thus, we studied only the most dominant characteristic wavelet signatures.

The wavelet spectra of waves in the dense slab and current sheet can differ in additional wavelet components that appear in association with the main tadpole structure. While in the dense slab this additional component can be delayed after the tadpole head, in the current sheet this component can precede the tadpole head. It could help distinguish a type of the waveguide in observed data.