Plasma wave resonance ($n^2\to \infty$)

A limiting point of a plasma wave branch with divergent refractive index. At finite coefficients of the magnetized cold-plasma dielectric tensor, the generic condition is $S{\sin }^2\theta +P{\cos }^2\theta =0$. Poles of that magnetized cold-plasma dielectric tensor require a separate limiting analysis. Collisions, thermal dispersion or mode conversion can regularize a singular cold prediction.