Eur. Phys. J. D 51, 233-240 (2009)
https://doi.org/10.1140/epjd/e2008-00286-8

Planar and nonplanar ion-acoustic envelope solitary waves in a very dense electron-positron-ion plasma

¹ Institut für Theoretische Physik IV, Fakultät für Physik und Astronomie, Ruhr-Universität Bochum, 44780 Bochum, Germany
² Theoretical Physics Group, Department of Physics, Faculty of Science, Mansoura University, Damietta Branch, 34517 New Damietta, Egypt
³ Department of Physics, Faculty of Science-Port Said, Suez Canal University, Port Said, Egypt
⁴ The Nonlinear Physics Centre & Center for Plasma Science and Astrophysics, Ruhr-Universität Bochum, 44780 Bochum, Germany
⁵ Department of Physics, Umeå University, 90187 Umeå, Sweden
⁶ Max-Planck-Institut für extraterrestrische Physik, 85741 Garching, Germany
⁷ GoLP/Institute of Plasmas and Nuclear Fusion, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
⁸ CCLRC Centre for Fundamental Physics, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon 0X11 0, QX, UK
⁹ SUPA Department of Physics, University of Strathclyde, Glasgow G 40, NG, UK
¹⁰ School of Physics, Faculty of Science & Agriculture, University of Kwazulu-Natal, Durban, 4000, South Africa
¹¹ Department of Physics, CITT, Islamabad, Pakistan

Corresponding authors: ^a sabryphys@yahoo.com sabry@tp4.rub.de

Received: 19 September 2008
Revised: 26 November 2008
Published online: 9 January 2009

Abstract

Ion-acoustic envelope solitary waves in a very dense plasma comprised of the electrons, positrons and ions are investigated. For this purpose, the quantum hydrodynamic model and the Poisson equation are used. A modified nonlinear Schrödinger equation is derived by employing the reductive perturbation method. The effects of the quantum correction and of the positron density on the propagation and stability of the envelope solitary waves are examined. The nonplanar (cylindrical/spherical) geometry gives rise to an instability period. The latter cannot exist for planar case and it affected by the quantum parameters, as well as the positron density. The present investigation is relevant to white dwarfs.