  The problem of standing wave formation by superposing two counter-propagating
whistler waves in an overdense plasma, studied recently by Sano et al. (Phys.
Rev. E 100, 053205 (2019) and Phys. Rev. E 101, 013206 (2020)), has been
revisited in the relativistic limit. A detailed theory along with simulation
has been performed to study the standing wave formation in the interaction of
two counter propagating relativistically intense whistler waves. The
relativistic theory explains such interaction process more precisely and
predicts correct field amplitudes of the standing wave for a much wider range
of physical parameters of the problem as compared to its non-relativistic
counterpart. The analytical results are compared with 1-D Particle-in-Cell
(PIC) simulation results, performed using OSIRIS 4.0. The results are of
relevance to ion heating and fast ignition scheme of inertial confinement
fusion.
