Coexistence of positive and negative polarity dust ion acoustic excitations with $$\kappa $$-deformed Kaniadakis distribution

2021 ◽  
Vol 136 (12) ◽  
Author(s):  
S. N. Naeem ◽  
Anisa Qamar ◽  
Muhammad Khalid ◽  
Ata ur Rahman
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Debdatta Debnath ◽  
Anup Bandyopadhyay

Abstract At the acoustic speed, we have investigated the existence of ion-acoustic solitary structures including double layers and supersolitons in a collisionless magnetized plasma consisting of negatively charged static dust grains, adiabatic warm ions, and nonthermal electrons. At the acoustic speed, for negative polarity, the system supports solitons, double layers, supersoliton structures after the formation of double layer, supersoliton structures without the formation of double layer, solitons after the formation of double layer whereas the system supports solitons and supersolitons without the formation of double layer for the case of positive polarity. But it is not possible to get the coexistence of solitary structures (including double layers and supersolitons) of opposite polarities. For negative polarity, we have observed an important transformation viz., soliton before the formation of double layer → double layer → supersoliton → soliton after the formation of double layer whereas for both positive and negative polarities, we have observed the transformation from solitons to supersolitons without the formation of double layer. There does not exist any negative (positive) potential solitary structures within 0 < μ < μ c (μ c < μ < 1) and the amplitude of the positive (negative) potential solitary structure decreases for increasing (decreasing) μ and the solitary structures of both polarities collapse at μ = μ c, where μ c is a critical value of μ, the ratio of the unperturbed number density of electrons to that of ions. Similarly there exists a critical value β e2 of the nonthermal parameter β e such that the solitons of both polarities collapse at β e = β e2.


2013 ◽  
Vol 79 (5) ◽  
pp. 817-823 ◽  
Author(s):  
ATA-UR RAHMAN ◽  
S. ALI ◽  
A. MUSHTAQ ◽  
A. QAMAR

AbstractThe dynamics and propagation of ion acoustic (IA) waves are considered in an unmagnetized collisionless plasma, whose constituents are the relativistically degenerate electrons and positrons as well as the inertial cold ions. At a first step, a linear dispersion relation for IA waves is derived and analysed numerically. For nonlinear analysis, the reductive perturbation technique is used to derive a Korteweg–deVries equation, which admits a localized wave solution in the presence of relativistic degenerate electrons and positrons. It is shown that only compressive IA solitary waves can propagate, whose amplitude, width and phase velocity are significantly modified due to the positron concentration. The latter also strongly influences all the relativistic plasma parameters. Our present analysis is aimed to understand collective interactions in dense astrophysical objects, e.g. white dwarfs, where the lighter species electrons and positrons are taken as relativistically degenerate.


2014 ◽  
Vol 81 (1) ◽  
Author(s):  
Ata Ur-Rahman ◽  
S. Ali ◽  
A. Mushtaq ◽  
A. Qamar

A misprint occured in equation 26 in the original article (Ur-Rahman et al. 2013). The correct equation is provided below. \[ \zeta=\epsilon^{1/2}\left(x-\lambda t\right) \rm{, \ \ }\tau=\epsilon^{3/2}t\rm{.}% \] This misprint does not affect the calculations, the figures and the discussion presented in the original article.


2017 ◽  
Vol 24 (9) ◽  
pp. 092114 ◽  
Author(s):  
Chérif S. Panguetna ◽  
Conrad B. Tabi ◽  
Timoléon C. Kofané

2017 ◽  
Vol 95 (7) ◽  
pp. 655-661 ◽  
Author(s):  
Ata-ur Rahman ◽  
A. Qamar ◽  
S. Naseer ◽  
S.N. Naeem

The linear and nonlinear propagation of ion acoustic waves is considered in a degenerate magnetoplasma, composed of relativistic degenerate electrons and an inertial ion fluid. A linear dispersion relation is derived in the linear approximation. The Sagdeev pseudopotential approach is used to investigate the properties of arbitrary amplitude, obliquely propagating ion acoustic solitary waves. The expression for the lower and upper Mach numbers for the existence of magnetized ion acoustic solitons has also been derived. The significant influence on the properties of soliton structures of relevant physical parameters, such as the plasma number density, the obliqueness (the angle between soliton propagation direction and magnetic field), and the soliton speed is also investigated. At the end, analytical results are supplemented through numerical analysis by using typical representative parameters consistent with degenerate and ultra-relativistic magnetoplasmas of astrophysical regimes.


2002 ◽  
Vol 16 (2) ◽  
pp. 114-118 ◽  
Author(s):  
Timo Ruusuvirta ◽  
Heikki Hämäläinen

Abstract Human event-related potentials (ERPs) to a tone continuously alternating between its two spatial loci of origin (middle-standards, left-standards), to repetitions of left-standards (oddball-deviants), and to the tones originally representing these repetitions presented alone (alone-deviants) were recorded in free-field conditions. During the recordings (Fz, Cz, Pz, M1, and M2 referenced to nose), the subjects watched a silent movie. Oddball-deviants elicited a spatially diffuse two-peaked deflection of positive polarity. It differed from a deflection elicited by left-standards and commenced earlier than a prominent deflection of negative polarity (N1) elicited by alone-deviants. The results are discussed in the context of the mismatch negativity (MMN) and previous findings of dissociation between spatial and non-spatial information in auditory working memory.


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