Heavy nucleus-acoustic spherical solitons in self-gravitating super-dense plasmas

Abstract

Heavy nucleus-acoustic (HNA) spherical solitons (SSs) associated with HNA waves (in which the inertia is provided by the heavy and light nuclear species, and restoring force is provided by the degenerate pressure of electron species) in self-gravitating degenerate (super-dense) quantum plasmas have been theoretically investigated. The reductive perturbation method has been employed to derive a modified Korteweg-de Vries equation. The new basic features (e.g., polarity, amplitude, width, etc.) of the HNA SSs (associated with electrostatic and self-gravitational potentials) are identified, and are found to be significantly modified by the effects of ultra-relativistically degenerate electron pressure, dynamics of non-degenerate light and heavy nuclear species, self-gravitational field, and spherical geometry. It is found that depending on the plasma parameters, the HNA SSs with either positive (negative) or negative (positive) electrostatic (self-gravitational) potential exist in such realistic astrophysical plasma systems. The applications of our results in some astrophysical compact objects (containing heavy and light nuclear species, and degenerate electron species) are briefly discussed.

Planar and non-planar nucleus-acoustic solitary waves in warm degenerate multi-nucleus plasmas

“…Recently, a number of theoretical investigations (Mamun, Amina & Schlickeiser 2016Zaman et al 2017Zaman et al , 2018Chowdhury et al 2018;Jannat & Mamun 2018a,b;Das & Karmakar 2019) have been made of the nonlinear propagation of NA waves in degenerate plasma systems. Mamun et al (2016Mamun et al ( , 2017 considered the strongly (Mamun et al 2016) and weakly (Mamun et al 2017) coupled heavy nucleus fluid, and studied the small-amplitude heavy NA shock waves (Mamun et al 2016) and solitary waves (SWs) (Mamun et al 2017) in an absolutely cold degenerate electron-light nucleus plasma system. These shock waves and SWs (Mamun et al 2016(Mamun et al , 2017 are associated with the dynamics of the heavy nucleus species, but not with that of the light nucleus species.…”

“…Mamun et al (2016Mamun et al ( , 2017 considered the strongly (Mamun et al 2016) and weakly (Mamun et al 2017) coupled heavy nucleus fluid, and studied the small-amplitude heavy NA shock waves (Mamun et al 2016) and solitary waves (SWs) (Mamun et al 2017) in an absolutely cold degenerate electron-light nucleus plasma system. These shock waves and SWs (Mamun et al 2016(Mamun et al , 2017 are associated with the dynamics of the heavy nucleus species, but not with that of the light nucleus species. Zaman et al (2017Zaman et al ( , 2018 have examined the effects of non-planar geometry on the NA shock (Zaman et al 2017) and solitary (Zaman et al 2018) waves propagating in absolutely cold degenerate electron-nucleus plasma systems.…”

“…The works highlighted above are valid only for absolutely cold degenerate plasma species, but are not valid for degenerate plasma species at finite temperature, particularly for hot white dwarfs (Dufour et al 2008(Dufour et al , 2011Werner & Rauch 2015;Werner, Rauch & Reindl 2019;Koester, Kepler & Irwin 2020). To overcome this limitation in previously published works (Mamun et al 2016(Mamun et al , 2017Zaman et al 2017Zaman et al , 2018Chowdhury et al 2018;Jannat & Mamun 2018a,b;Das & Karmakar 2019), the equation of state for a degenerate plasma at finite temperature (Manfredi 2005;Vavrukh & Smerechynskyi 2012;Hossain & Mandal 2019) is derived by quantum field theory (Hossain & Mandal 2019) and by introducing two parameters, namely σ j = m j c 2 /E Fj and σ Tj = k B T j /E Fj , where E Fj (T j ) is the the Fermi energy (temperature) of species j with k B being the Boltzmann constant. The equation of state (1.1) for plasma species j at finite temperature T j can, therefore, be modified as…”

Self‐gravito‐acoustic waves and their instabilities in a self‐gravitating degenerate quantum plasma system

“…The SGDQP system will be in equilibrium when this outward degenerate pressure of all the degenerate plasma species is counterbalanced by the inward poll of the same by the self-gravitational pressure. A large number of authors [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] have considered the degenerate plasma systems including/excluding the effect of self-gravitational field to study the electro/magneto-acoustic linear/nonlinear waves, but not to study any kind of self-gravito-acoustic (SGA) waves. white dwarfs, neutron stars, etc.…”

“…Once the SGDQP system is perturbed, new waves (which can be referred to as "degenerate pressure driven self-gravito-acoustic [DPDSGA] waves") are emitted because of its compression and rarefaction, and vice-versa. A large number of authors [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] have considered the degenerate plasma systems including/excluding the effect of self-gravitational field to study the electro/magneto-acoustic linear/nonlinear waves, but not to study any kind of self-gravito-acoustic (SGA) waves. Thus, in the present work, we investigate the DPDSGA waves to identify their dispersion properties and stable/unstable regimes depending on degenerate quantum plasma parameters.…”