Global surface wave resonances of the earth magnetosphere and their   possible manifestation
  In this paper global surface wave modes supported by plasma discontinuities at both the magnetopause and the plasmapause are considered. The ionosphere at the ends of the magnetic field lines of the earth outer magnetosphere is considered as reflecting boundaries of the surface waves that propagate along the plasma boundaries. As a result a standing wave structure along the magnetic field fluxes of the outer magnetosphere, i.e. surface wave resonance structure can be formed. Due to quantized wavenumbers along the magnetic field lines, the surface wave resonance possesses quantified frequencies in a following way: f = nfres, where fres is frequency of the corresponding fundamental surface wave resonance and n is an integer. Global Pc5 pulsations have been observed and interpreted mostly as cavity modes of the earth magnetosphere. The global Pc5 pulsations however could alternatively be interpreted as ultra low-frequency surface wave resonances of the earth magnetosphere that do not necessarily involve the cavity mode-field aligned resonance transformation concept. 
Petko Nenovski
physics.space-ph physics.geo-ph