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dc.contributor.authorGuio, Patrick
dc.contributor.authorLilensten, J.
dc.contributor.authorKofman, W.
dc.contributor.authorBjørnå, Noralv
dc.date.accessioned2007-01-24T09:53:41Z
dc.date.available2007-01-24T09:53:41Z
dc.date.issued1998-10-31
dc.description.abstractThe plasma dispersion function and the reduced velocity distribution function are calculated numerically for any arbitrary velocity distribution function with cylindrical symmetry along the magnetic field. The electron velocity distribution is separated into two distributions representing the distribution of the ambient electrons and the suprathermal electrons. The velocity distribution function of the ambient electrons is modelled by a near-Maxwellian distribution function in presence of a temperature gradient and a potential electric field. The velocity distribution function of the suprathermal electrons is derived from a numerical model of the angular energy flux spectrum obtained by solving the transport equation of electrons. The numerical method used to calculate the plasma dispersion function and the reduced velocity distribution is described. The numerical code is used with simulated data to evaluate the Doppler frequency asymmetry between the up- and downshifted plasma lines of the incoherent-scatter plasma lines at different wave vectors. It is shown that the observed Doppler asymmetry is more dependent on deviation from the Maxwellian through the thermal part for high-frequency radars, while for low-frequency radars the Doppler asymmetry depends more on the presence of a suprathermal population. It is also seen that the full evaluation of the plasma dispersion function gives larger Doppler asymmetry than the heat flow approximation for Langmuir waves with phase velocity about three to six times the mean thermal velocity. For such waves the moment expansion of the dispersion function is not fully valid and the full calculation of the dispersion function is needed.en
dc.descriptionSource at <a href=https://doi.org/10.1007/s00585-998-1226-z>https://doi.org/10.1007/s00585-998-1226-z</a>
dc.format.extent2875697 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.citationAnnales Geophysicae 16(1998), pp 1226-1240.
dc.identifier.doihttps://doi.org/10.1007/s00585-998-1226-z
dc.identifier.issn1432-0576 (elektronisk)
dc.identifier.urihttps://hdl.handle.net/10037/555
dc.identifier.urnURN:NBN:no-uit_munin_382
dc.language.isoengen
dc.publisherEuropean Geophysical Societyen
dc.rights.accessRightsopenAccess
dc.subjectNon-Maxwellian electron velocity distributionen
dc.subjectIncoherent scatter plasma linesen
dc.subjectEiscaten
dc.subjectDielectric response functionen
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Fysikk: 430::Elektromagnetisme, akustikk, optikk: 434en
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Fysikk: 430::Rom- og plasmafysikk: 437en
dc.titleElectron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal electrons: application to incoherent-scatter plasma lines.en
dc.typeJournal articleen
dc.typeTidsskriftartikkelno


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