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dc.contributor.authorZhao, J.S.
dc.contributor.authorVoitenko, Y.
dc.contributor.authorWu, D.J.
dc.contributor.authorDe Keyser, J.
dc.date2014
dc.date.accessioned2016-03-25T09:42:09Z
dc.date.available2016-03-25T09:42:09Z
dc.identifier.urihttps://orfeo.belnet.be/handle/internal/2808
dc.descriptionWe study the nonlocal nonlinear coupling and generation of kinetic Alfvén waves (KAWs) and kinetic slow waves (KSWs) by magnetohydrodynamic Alfvén waves (MHD AWs) in conditions typical for the solar wind in the inner heliosphere. This cross-scale process provides an alternative to the turbulent energy cascade passing through many intermediate scales. The nonlinearities we study are proportional to the scalar products of wave vectors and hence are called "scalar" ones. Despite the strong Landau damping of kinetic waves, we found fast growing KAWs and KSWs at perpendicular wavelengths close to the ion gyroradius. Using the parametric decay formalism, we investigate two independent decay channels for the pump AW: forward decay (involving co-propagating product waves) and backward decay (involving counter-propagating product waves). The growth rate of the forward decay is typically 0.05 but can exceed 0.1 of the pump wave frequency. The resulting spectral transport is nonlocal and anisotropic, sharply increasing perpendicular wavenumbers but not parallel ones. AWs and KAWs propagating against the pump AW grow with about the same rate and contribute to the sunward wave flux in the solar wind. Our results suggest that the nonlocal decay of MHD AWs into KAWs and KSWs is a robust mechanism for the cross-scale spectral transport of the wave energy from MHD to dissipative kinetic scales in the solar wind and similar media.
dc.languageeng
dc.titleNonlinear generation of kinetic-scale waves by magnetohydrodynamic alfvén waves and nonlocal spectral transport in the solar wind
dc.typeArticle
dc.subject.frascatiPhysical sciences
dc.audienceScientific
dc.subject.freeinstabilities
dc.subject.freeplasmas
dc.subject.freesolar wind
dc.subject.freeturbulence
dc.subject.freewaves
dc.source.titleAstrophysical Journal
dc.source.volume785
dc.source.issue2
dc.source.pageA139
Orfeo.peerreviewedYes
dc.identifier.doi10.1088/0004-637X/785/2/139
dc.identifier.scopus2-s2.0-84897991984


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