caa a22 4500 386367817 CHVBK 20180307111942.0 cr unu---uuuuu 161130e198912 xx s 000 0 eng 10.1017/S0022377800014446 doi S0022377800014446 pii (NATIONALLICENCE)cambridge-10.1017/S0022377800014446 Verheest Frank Instituut voor theoretische mechanika, Rijksuniversiteit Gent, Krijgslaan 281, B-9000 Gent, Belgium Ion-acoustic double layers in multi-species plasmas maintained by negative ions [Elektronische Daten] [Frank Verheest] A study is made of ion-acoustic double layers in a plasma consisting of any number of cold positive and negative ion (and cold electron) species in addition to one isothermal electron population. The Sagdeev potential is obtained in general, together with limits on both compressive and rarefactive solutions for ion-acoustic double layers and/or solitons. Weak ion-acoustic double layers are described by a modified Korteweg-de Vries equation. Such double layers are not possible in plasmas with only positive ion species and one electron population. When one or more negative ion and/or cold electron species are included above a certain threshold density, rarefactive ion-acoustic double layers occur, but no compressive ones. The double-layer form of the potential is given, together with an application to a plasma with one positive and one negative ion component. It is shown that there is indeed such a threshold density for the negative ion density, depending on the charge-to-mass ratios of both types of ions. The threshold density is determined numerically for a range of such ratios and discussed in view of possible relevance to auroral and experimental plasmas. In the discussion, cold electrons can play the role of the negative ion species. Copyright © Cambridge University Press 1989 Journal of Plasma Physics Cambridge University Press 42/3(1989-12), 395-406 0022-3778 42:3<395 1989 42 PLA https://doi.org/10.1017/S0022377800014446 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0022377800014446 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Verheest Frank Instituut voor theoretische mechanika, Rijksuniversiteit Gent, Krijgslaan 281, B-9000 Gent, Belgium NATIONALLICENCE 773 0- Journal of Plasma Physics Cambridge University Press 42/3(1989-12), 395-406 0022-3778 42:3<395 1989 42 PLA CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge