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A shear flow instability in a nonuniform partially ionized magnetoplasma has been investigated and the angular momentum transport of charged particles caused by drift waves has been estimated. The angular momentum transport of the electrons and ions is not equal because the system is not conservative. The present investigation should help to understand the origin of fluctuations and associated parallel momentum transport of charged particles in nonuniform laboratory and astrophysical plasmas with sheared ion flow. 相似文献
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Asif Shah 《Physics letters. A》2009,373(45):4164-4168
The Korteweg-de Vries-Burger (KdVB) equation is derived for ion acoustic shock waves in a weakly relativistic electron-positron-ion plasma. Electrons, positrons are considered isothermal and ions are relativistic. The travelling wave solution has been acquired by employing the tangent hyperbolic method. The vivid display of the graphical results is presented and analyzed. It is observed that amplitude and steepness of the shock wave decrease with increase of the relativistic streaming factor, the positron concentration and they increase with the increase of the coefficient of kinematic viscosity and vice versa. It is determined that at low temperature the shock wave propagates, whereas at very high temperature the solitary wave propagates in the system. The results may have relevance in astrophysical plasmas as well as in inertial confinement fusion plasmas. 相似文献
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Subharmonic resonant beat-wave excitation of nonlinear relativistic plasma waves is studied analytically and in particle-in-cell simulations. We find that if the frequency separation of the lasers, Deltaomega, is 2omega(p) or 3omega(p) ( omega(p) is the plasma frequency), then plasma waves are still excited at omega(p) but they grow exponentially or superexponentially rather than secularly. Both of these subharmonic resonant instabilities saturate due to relativistic detuning. The analytical growth rates and saturation levels agree with the simulation results. 相似文献
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M. S. Sodha S. C. Kaushik V. K. Tripathi 《Applied Physics A: Materials Science & Processing》1974,3(2):141-148
The free carrier nonlinear dielectric constant of a degenerate electron-hole plasma (e.g., Ge) in the presence of a Gaussian
electromagnetic beam has been studied by a kinetic treatment. The redistribution of carriers (electrons and holes) is the
source of nonlinearity and is effective in causing the self-focusing of the beam. The rise in carrier temperature due to the
wave field is almost unaffected by the degeneracy, whereas the nonlinearity is considerably affected by it. The increase of
degeneracy (by increasing the equilibrium carrier concentration at the fixed lattice temperature) increases the nonlinear
dielectric constant. Hence self-focusing is enhanced by degeneracy.
This work was supported by NSF (USA) and CSIR (India). 相似文献
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Summary The Korteweg-de Vries equation for ion acoustic waves in the presence of weakly relativistic ion streaming velocity is derived
in a magnetic plasma. It is found that relativistic effects are important in the solitary wave propagation for both fast and
slow modes. Earlier results are reconfirmed.
To speed up publication, the authors of this paper have agreed to not receive the proofs for correction. 相似文献
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Ion-acoustic waves (IAWs) in a quantum electron-ion plasma with degenerate components are theoretically investigated using a system of quantum equations of gas dynamics that allow for the quantum-size character of the object (Bohm’s quantum force is included in the equation of motion) and the Pauli exclusion principle (equations of state for degenerate Fermi gases of electrons and ions are used). Linear analysis and numerical solution of equations yielded an identical qualitative result: periodic IAWs in a quantum electron-ion plasma are always a superposition of two waves with equal phase velocities but different wavelengths. The high-frequency component of the IAW is identified with free quantum oscillations of ions. A solution in the form of an ion-sound soliton with free quantum oscillations of ions superposed on its profile is also found. 相似文献
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Nonlinear propagation of ion-acoustic (IA) waves in a degenerate dense plasma (with all the constituents being degenerate, for both the non-relativistic or ultrarelativistic cases) have been investigated by the reductive perturbation method. The linear dispersion relation and Korteweg–de Vries (KdV) equation have been derived, and the numerical solutions of KdV equation have been analysed to identify the basic features of electrostatic solitary structures that may form in such a degenerate dense plasma. The implications of our results in compact astrophysical objects, particularly, in white dwarfs and neutron stars, have been briefly discussed. 相似文献
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M.K. Islam S. Biswas N.A. Chowdhury A. Mannan M. Salahuddin AA Mamun 《等离子体物理论文集》2022,62(1):e202100073
A theoretical investigation has been carried out on the propagation of non-linear ion-acoustic shock waves (IASHWs) in a magnetized degenerate quantum plasma system composed of inertial non-relativistic positively charged light and heavy ions, inertialess non-relativistically or ultra-relativistically degenerate electrons and positrons. The reductive perturbation method has been employed to derive the Burgers' equation. It has been observed that under consideration, our plasma model supports only positive potential shock structure. It is also found that the amplitude and steepness of the IASHWs have been significantly modified by the variation of ion kinematic viscosity, oblique angle, number density, and charge state of the plasma species. The results of our present investigation will be helpful for understanding the propagation of IASHWs in white dwarfs and neutron stars. 相似文献
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The longitudinal dielectric response of a relativistic ultra-degenerate electron plasma in a strong magnetic field is obtained via a relativistic generalization of the Hartree self-consistent field method. Dispersion relations and damping conditions for plasma oscillations both parallel and perpendicular to the magnetic field are obtained. We also give detailed results for the zero-field case. Applications to white dwarf stars and pulsars are given. 相似文献
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Due to the presence of a relatively cold electron component in a plasma, the ion acoustic solitary wave of a given width has a larger amplitude. When the temperature difference between the two electron components is sufficiently large, the strength of dispersion is reduced to an extent that a solitary solution is no longer possible. 相似文献
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A dispersion relation for the perpendicular propagation of the electromagnetic ion cyclotron wave around the second harmonic
of the deuterium ion gyrofrequency in a mildly relativistic, anisotropic Maxwellian plasma with hydrogen as the majority species
and deuterium as the minority component has been derived. The work has been carried out in the frame of reference of the majority
hydrogen ions; to these ions the waves at 2ΘD would be at its own gyrofrequency.
Using a small quantityɛ to order all relevant parameters of the plasma, it was possible to derive the dispersion relations in a simple form. To the
lowest order the relativistic factors do not enter the dispersion relation. The plasma can now support two modes—one above
and the other below the hydrogen gyrofrequency in agreement with the assumptions. This was also verified numerically using
a standard root solver thereby justifying the correctness of the ordering scheme.
In the next higher order, the dispersion relation is a quartic equation and is sensitively dependent on the relativistic factors.
The plasma can now support four modes, both above and below the hydrogen gyrofrequency and consistent with the ordering scheme
used. However the modes can now coalesce resulting in complex conjugate roots to the dispersion relation thereby indicating
an instability.
The advantage of such a scheme is that two dispersion relations — one of which is independent of the relativistic factors
and the other which is sensitively dependent on them can be separated out. 相似文献
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Malik H.K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1995,23(5):813-815
Modified Korteweg-deVries equation (mK-dV), which governs the behavior of ion acoustic solitons in a relativistic warm plasma with density gradient, is derived. The electron inertia is also taken into account which is important when the streaming ions are present in the plasma. A solution of the mK-dV equation is obtained for the constant density gradient. When the ion acoustic soliton propagates into the lower plasma density region, its amplitude and energy increase, but the width decreases; the same is the case for the stronger density gradients 相似文献
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I. S. Ognev 《Journal of Experimental and Theoretical Physics》2016,123(4):643-665
The effect of a magnetic field of arbitrary strength on the beta decay and crossing symmetric processes is analyzed. A covariant calculation technique is used to derive the expression for the squares of S-matrix elements of these reactions, which is also valid in reference frames in which the medium moves as a single whole along magnetic field lines. Simple analytic expressions obtained for the neutrino and antineutrino emissivities for a moderately degenerate plasma fully characterize the emissivity and absorbability of the studied medium. It is shown that the approximation used here is valid for core collapse supernovae and accretion disks around black holes; beta processes in these objects are predominantly neutrino reactions. The analytic expressions obtained for the emissivities can serve as a good approximation for describing the interaction of electron neutrinos and antineutrinos with the medium of the objects in question and hold for an arbitrary magnetic field strength. Due to their simplicity, these expressions can be included in the magnetohydrodynamic simulation of supernovae and accretion disks to calculate neutrino and antineutrino transport in them. The rates of beta processes and the energy and momentum emitted in them are calculated for an optically transparent matter. It is shown that the macroscopic momentum transferred in the medium increases linearly with the magnetic field strength and can substantially affect the dynamics of supernovae and accretion disks in the regions of a degenerate matter. It is also shown that the rates of beta processes and the energy emission for a magnetic field strength of B ? 1015 G typical of supernovae and accretion disks are lower than in the absence of field. This suppression is stronger for reactions with neutrinos. 相似文献
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Hamid Reza Pakzad 《Indian Journal of Physics》2009,83(11):1605-1613
The Korteweg-de Vries equation for a weakly relativistic ion acoustic wave propagating in oollisionless plasma containing
nonthermal electron, positron and warm ion is derived. The effects of the ion temperature, nonthermal parameter and relativistic
effect on the amplitude, width and energy of soliton are studied. 相似文献