Nonlinear electrostatic solitary pulses in magnetized quantum plasma with relative density effects of spin-up and spin-down electrons

Abstract

A separated spin evolution quantum hydrodynamics model is employed to study low frequency electrostatic waves in plasmas having inertia-less degenerate electrons with spin-up ne↑ and spin-down ne↓ states and inertial classical ions. A two-dimensional plasma geometry is assumed having a uniform magnetic field, directed along the z-axis, i.e., B=B0ẑ. A Zakharov-Kuznetsov (ZK) type equation is derived for the electrostatic potential via the Reductive Perturbation Technique. The parametric role of the spin density polarization ratio κ in the characteristics of solitary wave structures is investigated. We have observed that both the amplitude and width of the soliton are significantly affected by the spin polarization but the amplitude remains largely un-affected by variation in the magnetic field strength. We have also carried out pulse stability analysis and have found that the pulse soliton solution of the ZK equation is unstable to oblique perturbations. The dependence of the instability growth rate on the density polarization ratio κ along with other significant plasma parameters is traced analytically. We have shown that the first order growth rate of the instability decreases with an increase in the angle between the transverse component of the perturbation and the direction of the magnetic field, in the range (0≤θ<37.8°). We have also observed that the spin polarization affects the growth and increases as we move from the strongly spin-polarized plasma to a zero polarization case.

Ion-Acoustic Cnoidal Waves with the Density Effect of Spin-up and Spin-down Degenerate Electrons in a Dense Astrophysical Plasma

“…In the limiting case, when coefficient C vanishes in (38) of [20] and in (29) of [21], one can get the KdV equation, which agrees with (30) (for C = 0) in the present investigation.…”

“…Owing to the presence of spin-up and spin-down electrons in a degenerate quantum plasma, some investigations focusing on the study of solitary and shock waves have been reported. Ahmad et al [20] investigated the lowfrequency electrostatic waves in plasmas having inertialess degenerate electrons by employing the separated spin evolution QHD model. The pulse stability analysis was carried out, and it was also found that spin polarisation significantly affects the amplitude and width of the solitary waves.…”

Kinetic description of the oblique propagating spin-electron acoustic waves in degenerate plasmas

“…A significant influence of the spin polarization on the amplitude and width of the acoustic dark soliton (presented in terms of the scalar potential of the electromagnetic field) is found for the magnetized electron-ion plasmas in Ref. [23]. It is demonstrated that the increase of the spin polarization leads to the increase of the module of the soliton amplitude.…”

Oblique propagation of longitudinal spin-electron acoustic waves under the influence of the Coulomb exchange interaction and the quantum Bohm potential

“…Majority of application of the separate spin evolution quantum hydrodynamics (SSE-QHDs) is related to the spin-electron acoustic waves (SEAWs). However, there are papers devoted to the influence of the separate spin evolution and the spin polarized Fermi pressure on the following phenomena: Raman three-wave interaction for the pump wave (O-mode), sideband Shear Alfven wave, and the electron * Electronic address: andreevpa@physics.msu.ru plasma perturbations [33], and non-linear propagation of ion-acoustic waves [34].…”