a Snapshot of the vertical component of the magnetic field of a TE GPP in magnetized CNG, at B = 1.3 T. b Propagation length and wavelength of the TM GPP in magnetized CNG as a function of the magnetic field. c Dispersion relation for TE GPP in magnetized CNGs, calculated for different magnetic fields. d Real part of the z-component of magnetic field calculated for both B = 1.3 T and B = 1.4 T (the corresponding GPP wavelengths are λpl = 26.32 μm and λpl = 26.66 μm, respectively). For comparison, the free-space wave oscillation (with wavelength λ0) is shown by the black curve. In all panels the frequency v = 11.2 THz (λ0 = 26.77 μm).