Dispersive MHD waves and alfvenons in charge non-neutral plasmas
2008 (English)In: Nonlinear processes in geophysics, ISSN 1023-5809, E-ISSN 1607-7946, Vol. 15, no 4, 681-693 p.Article in journal (Refereed) Published
Dispersive properties of linear and nonlinear MHD waves, including shear, kinetic, electron inertial Alfv´en, 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 ionsto 300–800 km/s. New results are discussed in the context of observations and other theoretical models for nonlinear Alfv´en waves in space plasmas.
Place, publisher, year, edition, pages
2008. Vol. 15, no 4, 681-693 p.
IdentifiersURN: urn:nbn:se:umu:diva-42824OAI: oai:DiVA.org:umu-42824DiVA: diva2:410478