The propagation of ion-acoustic waves carrying orbital angular momentum in the electron–positron–ion plasmas

Autor: Davod Nobahar, Hassan Mehdian, K. Hajisharifi
Rok vydání: 2018
Předmět:
Zdroj: Indian Journal of Physics. 92:1169-1176
ISSN: 0974-9845
0973-1458
Popis: Ion-acoustic (IA) waves carrying orbital angular momentum (OAM) are investigated in an unmagnetized, uniform, and collisionless electron–positron–ion (e–p–i) plasma system. Employing the hydrodynamic theory, the paraxial equation in term of ion perturbed number density is derived and discussed about its Laguerre–Gaussian (LG) beam solutions. Obtaining an approximate solution for the electrostatic potential, the IA wave characteristics including helical electric field structure, energy density, and OAM density are theoretically studied. Based on the numerical analysis, the effects of positron concentration, radial and angular mode number as well as beam waist on the obtained potential profile are investigated. It is shown that the depth (height) and width of the LG potential profile wells (barriers) are considerably modify by the variation of positron concentration.
Databáze: OpenAIRE