Show simple item record Ballai, I. Pinter, B. Oliver, R. Alexandrou, M. 2017-07-27T18:34:38Z 2017-07-27T18:34:38Z 2017-07-10
dc.identifier.citation Ballai , I , Pinter , B , Oliver , R & Alexandrou , M 2017 , ' Dissipative instability in a partially ionised prominence plasma slab ' Astronomy and Astrophysics , vol 603 , A78 . DOI: 10.1051/0004-6361/201629215 en
dc.identifier.issn 0004-6361
dc.identifier.other PURE: 18637199
dc.identifier.other PURE UUID: 8d112aaf-e580-4336-824a-8148f24dc384
dc.identifier.other Scopus: 85023782332
dc.identifier.other 2160/45412
dc.description.abstract Aims. We aim to investigate the nature of dissipative instability appearing in a prominence planar thread filled with partially ionised plasma in the incompressible limit. The importance of partial ionisation is investigated in terms of the ionisation factor and the wavelength of sausage and kink waves propagating in the slab. Methods. In order to highlight the role of partial ionisation, we have constructed models describing various situations we can meet in solar prominence fine structure. Matching the solutions for the transversal component of the velocity and total pressure at the interfaces between the prominence slab and surrounding plasmas, we derived a dispersion relation whose imaginary part describes the evolution of the instability. Results were obtained in the limit of weak dissipation. We have investigated the appearance of instabilities in prominence dark plumes using single and two-fluid approximations. Results. Using simple analytical methods, we show that dissipative instabilities appear for flow speeds that are less than the Kelvin-Helmholtz instability threshold. The onset of instability is determined by the equilibrium flow strength, the ionisation factor of the plasma, the wavelength of waves and the ion-neutral collisional rate. For a given wavelength and for ionisation degrees closer to a neutral gas, the propagating waves become unstable for a narrow band of flow speeds, meaning that neutrals have a stabilising effect. Our results show that the partially ionised plasma describing prominence dark plumes becomes unstable only in a two-fluid (charged particles-neutrals) model, that is for periods that are smaller than the ion-neutral collision time. Conclusions. The present study improves our understanding of the complexity of dynamical processes and stability of solar prominences and the role partial ionisation in destabilising the plasma. We showed the necessity of two-fluid approximation when discussing the nature of instabilities: waves in a single fluid approximation show a great deal of stability. Our results clearly show that the problem of partial ionisation introduces new aspects of plasma stability with consequences on the evolution of partially ionised plasmas and solar prominences, in particular en
dc.format.extent 11 en
dc.language.iso eng
dc.relation.ispartof Astronomy and Astrophysics en
dc.rights en
dc.subject Sun: filaments, prominences en
dc.subject Sun: oscillations en
dc.title Dissipative instability in a partially ionised prominence plasma slab en
dc.type /dk/atira/pure/researchoutput/researchoutputtypes/contributiontojournal/article en
dc.description.version publishersversion en
dc.contributor.institution Department of Physics en
dc.description.status Peer reviewed en

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