Multi-dimensional instability of multi-ion acoustic solitary waves in a degenerate magnetized plasma

Abstract

The multi-dimensional instability of obliquely propagating multi-ion acoustic (MIA) solitary structures was studied theoretically by the small-k (long wavelength plane wave) perturbation expansion technique in an ultra-relativistic degenerate magnetized plasma, which consists of inertia less electrons, inertial ions and stationary arbitrarily charged heavy ions. The Zakharov–Kuznetsov equation is derived by the reductive perturbation method and its solitary wave solution is analyzed. The basic properties of small but finite-amplitude MIA solitary waves have been modified significantly by the combined effects of the degenerate electron number density, heavy ion number density, external magnetic field and obliqueness. The underlying physics of the MIA solitary waves, which are relevant to space plasma situations, and the basic features, such as amplitude, width and growth rate, are briefly discussed.

Roles of arbitrarily charged heavy ions and degenerate plasma pressure in cylindrical and spherical IA shock waves

“…where ν = 0 for one-dimensional planar geometry, ν = 1 (ν = 2) for nonplanar cylindrical (spherical) geometry, n i (n e ) is the ion (electron) number density normalized by its equilibrium value n i0 (n e0 ), u i is the ion fluid speed normalized by 12 with m e (m i ) being the electron (ion) rest mass, c is the speed of light in vacuum, ϕ is the electrostatic wave potential normalized by m c e e 2…”

“…For some relatively massive white dwarfs, one can think of the presence of heavier elements like iron within the stars [8][9][10]. A white dwarf is a real example where degenerate electrons and heavy ions exist [11,12]. The density of the plasma constituents (electron and ion) in a white dwarf is of the order of 10 30 cm −3 [2].…”

Planar and Nonplanar Shock Waves in a Degenerate Quantum Plasma

“…These interstellar compact objects are contracted significantly and, as a result, the density of their interiors becomes extremely high to provide non-thermal pressure via degenerate fermion/electron pressure and particle-particle interactions. The observational evidence and theoretical analysis imply that these compact objects, which support themselves against gravitational collapse by cold degenerate fermion/electron pressure, are of two categories [18,19]. The interior of the first category is close to a dense solid (ion lattice surrounded by degenerate electrons, and possibly other heavy particles or dust).…”

“…One example of this kind of stars is a neutron star, which is supported by the pressure due to a combination of nucleon degeneracy and nuclear interactions. These unique states (extreme conditions) of matter occur by significant compression of the interstellar medium [18,19]. The degenerate electron or positron number density (number of electrons or positrons per unit volume) in such a compact object is so high (e.g., it can be of the order of 10 30 cm −3 and 10 36 cm −3 or more in white dwarfs and neutron stars, respectively) [20][21][22] that the electron Fermi energy is comparable to the electron mass energy and the electron speed is comparable to the speed of light in vacuum.…”

Nonlinear structure and growth rate of solitary waves for extended Zakharov-Kuznetsov equation in plasma having (r, q) distribution electrons

“…The study aims to contribute to the understanding of nonlinear IA waves in space and laboratory electron-positron-ion magneto-plasmas. Akter et al [39] studied the instability of obliquely propagating multi-ion acoustic (MIA) solitary structures in ultra-relativistic degenerate magnetized plasma consisting of inertialess electrons, inertial ions, and stationary arbitrarily charged heavy ions. They used the small-k perturbation expansion technique to theoretically study the MIA solitary structures and derived the Zakharov-Kuznetsov (ZK) equation.…”