External magnetic field effects on the dispersion properties of hybrid plasmon polariton (HPP) modes are theoretically investigated in a collisional warm magnetized planar conductor–gap– dielectric (CGD) system. This structure consists of a high index dielectric, separated from a warm metallic plasma with a low index nano-sized dielectric layer. The Magnetohydrodynamics model (MHD) coupled to Maxwell’s equations is used to derive the new dispersion relation of HPP waves in the CGD system. Numerical results reveal that the weakly external magnetic field which is parallel to the propagation wave has a significant effect on the dispersion properties of the guide modes and leads to an increase in the surface wave’s confinement and the propagation length of the HPP mode. Also, it is found that the critical gap thickness in the magnetized CGD system is bigger than the critical thickness in the unmagnetized CGD system.
