Articles | Volume 15, issue 4
Nonlin. Processes Geophys., 15, 681–693, 2008
https://doi.org/10.5194/npg-15-681-2008

Special issue: Nonlinear Processes in the Space Environment

Nonlin. Processes Geophys., 15, 681–693, 2008
https://doi.org/10.5194/npg-15-681-2008

  08 Aug 2008

08 Aug 2008

Dispersive MHD waves and alfvenons in charge non-neutral plasmas

K. Stasiewicz1,2 and J. Ekeberg1 K. Stasiewicz and J. Ekeberg
  • 1Swedish Institute of Space Physics, Uppsala and Kiruna, Sweden
  • 2Space Research Centre, Polish Academy of Sciences, Warsaw, Poland

Abstract. Dispersive properties of linear and nonlinear MHD waves, including shear, kinetic, electron inertial Alfvén, and slow and fast magnetosonic waves are analyzed using both analytical expansions and a novel technique of dispersion diagrams. The analysis is extended to explicitly include space charge effects in non-neutral plasmas. Nonlinear soliton solutions, here called alfvenons, are found to represent either convergent or divergent electric field structures with electric potentials and spatial dimensions similar to those observed by satellites in auroral regions. Similar solitary structures are postulated to be created in the solar corona, where fast alfvenons can provide acceleration of electrons to hundreds of keV during flares. Slow alfvenons driven by chromospheric convection produce positive potentials that can account for the acceleration of solar wind ions to 300–800 km/s. New results are discussed in the context of observations and other theoretical models for nonlinear Alfvén waves in space plasmas.