Electrostatic solitary waves in the presence of excess superthermal electrons: modulational instability and envelope soliton modes


Autoria(s): Sultana, Sharmin; Kourakis, Ioannis
Data(s)

01/04/2011

Resumo

The nonlinear dynamics of electrostatic solitary waves in the form of localized modulated wavepackets is investigated from first principles. Electron-acoustic (EA) excitations are considered in a two-electron plasma, via a fluid formulation. The plasma, assumed to be collisionless and uniform (unmagnetized), is composed of two types of electrons (inertial cold electrons and inertialess kappa-distributed superthermal electrons) and stationary ions. By making use of a multiscale perturbation technique, a nonlinear Schrodinger equation is derived for the modulated envelope, relying on which the occurrence of modulational instability (MI) is investigated in detail. Stationary profile localized EA excitations may exist, in the form of bright solitons (envelope pulses) or dark envelopes (voids). The presence of superthermal electrons modifies the conditions for MI to occur, as well as the associated threshold and growth rate. The concentration of superthermal electrons (i.e., the deviation from a Maxwellian electron distribution) may control or even suppress MI. Furthermore, superthermality affects the characteristics of solitary envelope structures, both qualitatively (supporting one or the other type, for different.) and quantitatively, changing their characteristics (width, amplitude). The stability of bright and dark-type nonlinear structures is confirmed by numerical simulations.

Identificador

http://pure.qub.ac.uk/portal/en/publications/electrostatic-solitary-waves-in-the-presence-of-excess-superthermal-electrons-modulational-instability-and-envelope-soliton-modes(1009295c-72da-4fd1-bf77-1a6bdd3c457f).html

http://dx.doi.org/10.1088/0741-3335/53/4/045003

Idioma(s)

eng

Direitos

info:eu-repo/semantics/restrictedAccess

Fonte

Sultana , S & Kourakis , I 2011 , ' Electrostatic solitary waves in the presence of excess superthermal electrons: modulational instability and envelope soliton modes ' Plasma Physics and Controlled Fusion , vol 53 , no. 4 , 045003 . DOI: 10.1088/0741-3335/53/4/045003

Palavras-Chave #/dk/atira/pure/subjectarea/asjc/2100/2104 #Nuclear Energy and Engineering #/dk/atira/pure/subjectarea/asjc/3100/3104 #Condensed Matter Physics
Tipo

article