arXiv subjects

M. Hosseinpour

Publications and source records attributed to M. Hosseinpour.

7 recordsLinked to original sources

arXiv2021

Interaction of the generalized Duffin-Kemmer-Petiau equation with a non-minimal coupling under the cosmic rainbow gravity

In this study, we survey the generalized Duffin-Kemmer-Petiau oscillator containing a non-minimal coupling interaction in the context of rainbow gravity in the presence of cosmic topological defects in space-time. In this regard, we intend to investigate relativistic quantum dynamics of a spin-0 particle under the modification of the dispersion relation according to the Katanaev-Volovich geometric approach. Thus, based on the geometric model, we study the aforementioned bosonic system under the modified background by a few rainbow functions. In this way, by using an analytical method, we acquire energy eigenvalues and corresponding wave functions corresponding to each scenario. Regardless of rainbow gravity function selection, the energy eigenvalue can present symmetric, anti-symmetric, and symmetry breaking characteristics. Besides, one can see that the deficit angular parameter plays an important role in the solutions.

quant-ph↗

arXiv2019

Effect of the Temperature of Background Plasma and the Energy of Energetic Electrons on Z-Mode Excitation

It has been suggested that the Z-mode instability driven by energetic electrons with a loss-cone type velocity distribution is one candidate process behind the continuum and zebra pattern of solar type-IV radio bursts. Both the temperature of background plasma ($T_0$) and the energy of energetic electrons ($v_e$) are considered to be important to the variation of the maximum growth rate ($γ_{max}$). Here we present a detailed parameter study on the effect of $T_0$ and $v_e$, within a regime of the frequency ratio ($10 \leq \frac{ω_{pe}}{Ω_{ce}} \leq 30$). In addition to $γ_{max}$, we also analyze the effect on the corresponding wave frequency ($ω^r_{max}$) and propagation angle ($θ_{max}$). We find that (1) $γ_{max}$ in-general decreases with increasing $v_e$, while its variation with $T_0$ is more complex depending on the exact value of $v_e$; (2) with increasing $T_0$ and $v_e$, $ω^r_{max}$ presents step-wise profiles with jumps separated by gradual or very-weak variations, and due to the warm-plasma effect on the wave dispersion relation $ω^r_{max}$ can vary within the hybrid band (the harmonic band containing the upper hybrid frequency) and the band higher; (3) the propagation is either perpendicular or quasi-perpendicular, and $θ_{max}$ presents variations in line with those of $ω^r_{max}$, as constrained by the resonance condition. We also examine the profiles of $γ_{max}$ with $\frac{ω_{pe}}{Ω_{ce}}$ for different combinations of $T_0$ and $v_e$ to clarify some earlier calculations which show inconsistent results.

astro-ph.SR↗

arXiv2016

Duffin-Kemmer-Petiau equation in curved space-time with scalar linear interactions

In this paper, we study the covariant Duffin-Kemmer-Petiau (DKP) equation in the space-time generated by a cosmic string and we examine the linear interaction of a DKP field with gravitational fields produced by topological defects and thus study the influence of topology on this system. We highlight two classes of solutions defined by the product of the deficit angle with the angular velocity of the rotating frame. We solve the covariant form of DKP equation in an exact analytical manner for node-less and one-node states by means of an appropriate ansatz.

math-ph↗

arXiv2015

DKP Equation in a Rotating Frame with Magnetic Cosmic String Background

We study the non-inertial effects on the covariant DKP equation in the curved space-time of a cosmic string. The calculations are done in the presence of a magnetic vector potential in the Coulomb gauge and the analytical solutions for the modified spectrum of the system are reported.

hep-th↗

arXiv2013

Transverse oscillations in solar spicules induced by propagating Alfvenic pulses

The excitation of Alfvenic waves in the solar spicules due to the localized Alfvenic pulse is investigated. A set of incompressible MHD equations in two dimensional $x-z$ plane with steady flows and sheared magnetic fields is solved. Stratification due to gravity and transition region between chromosphere and corona are taken into account. An initially localized Alfvenic pulse launched below the transition region can penetrate from transition region into the corona. We show that the period of transversal oscillations is in agreement with those observed in spicules. Moreover, it is found that the excited Alfvenic waves spread during propagation along the spicule length, and suffer efficient damping of the oscillations amplitude. The damping time of transverse oscillations elongated with decrease in k_b values.

astro-ph.SR↗

arXiv2012

Phase mixing of propagating Alfven waves in a stratified atmosphere: Solar spicules

Alfvenic waves are thought to play an important role in coronal heating and solar wind acceleration. Recent observations by Hinode/SOT showed that the spicules mostly exhibit upward propagating high frequency waves. Here we investigate the dissipation of such waves due to phase mixing in stratified environment of solar spicules. Since they are highly dynamic structures with speeds at about significant fractions of the Alfven phase speed, we take into account the effects of steady flows. Our numerical simulations show that in the presence of stratification due to gravity, damping takes place in space than in time. The exponential damping low, exp(-At^3), is valid under spicule conditions, however the calculated damping time is much longer than the reported spicule lifetimes from observations.

astro-ph.SR↗

arXiv2012

Phase mixing of standing Alfven waves with shear flows in solar spicules

Alfvenic waves are thought to play an important role in coronal heating and solar wind acceleration. Here we investigate the dissipation of such waves due to phase mixing at the presence of shear flow and field in the stratified atmosphere of solar spicules. The initial flow is assumed to be directed along spicule axis and to vary linearly in the x direction and the equilibrium magnetic field is taken 2-dimensional and divergence-free. It is determined that the shear flow and field can fasten the damping of standing Alfven waves. In spite of propagating Alfven waves, standing Alfven waves in Solar spicules dissipate in a few periods. As height increases, the perturbed velocity amplitude does increase in contrast to the behavior of perturbed magnetic field. Moreover, it should be emphasized that the stratification due to gravity, shear flow and field are the facts that should be considered in MHD models in spicules.

astro-ph.SR↗