Cold-plasma waves#
Linearizes the multi-fluid cold-plasma equations around a uniform
background to get the plasma frequency
(plasma_frequency()) and the Stix
dielectric tensor components \(S\), \(D\), \(P\)
(stix_parameters()), from which every
named cold-plasma wave mode follows as one quartic equation in the
refractive index (cold_plasma_dispersion()),
organized by the Clemmow-Mullaly-Allis (CMA) diagram
(cma_coordinates()). Beyond this linear,
dispersion-relation picture, the ion-acoustic soliton
(ion_acoustic_soliton_profile(),
ion_acoustic_soliton_evolve()) is a
genuinely nonlinear traveling wave, propagating without change of shape
under the Washimi-Taniuti Korteweg-de Vries reduction.
Stix’s cold-plasma dielectric tensor and the CMA diagram
Ion-acoustic solitons: a KdV pulse that never changes shape