@article{8478,
  author = {R. Keppens and J. P. Goedbloed},
  title = {Wave modes in a cold pair plasma: the complete phase and group diagram point-of-view},
  abstract = {We present a complete analysis of all wave modes in a cold pair plasma, significantly extending standard textbook treatments. Instead of identifying the maximal number of two propagating waves at fixed frequency w we introduce a unique labelling of all 5 mode pairs described by the general dispersion relation w(k), starting from their natural ordering at small wavenumber k. There, the 5 pairs start off as Alfvén (A), fast magnetosonic (F), modified electrostatic (M) and electromagnetic O and X branches, and each w(k) branch smoothly connects to large wavenumber resonances or limits. For cold pair plasmas, these 5 branches show avoided crossings, which become true crossings at exactly parallel or perpendicular orientation. Only for those orientations, we find a changed connectivity between small and large wavenumber behaviour. Analysing phase and group diagrams for all 5 wave modes, distinctly different from the Clemmow–Mullaly–Allis representation, reveals the true anisotropy of the A, M and O branches.
},
  year = {2019},
  journal = {Journal of Plasma Physics},
  volume = {85},
  pages = {175850101},
  doi = {10.1017/S0022377819000102},
  language = {eng},
}