| 1. |
- Gradov, O.M., et al.
(författare)
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Non-linear effects in a cold electron plasma with non-uniform density profile
- 2008
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 77, s. 055503-1-055503-3
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Tidskriftsartikel (refereegranskat)abstract
- A new step forward on the theory for two-dimensional wave propagation is outlined for a non-uniform plasma with a smooth density profile. A way to excite envelope solitary waves with certain shapes is described. The corresponding wave space structure is calculated, and the restrictions on the wave profile along the direction of wave propagation are noticed.
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| 2. |
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| 3. |
- Onishchenko, O G, et al.
(författare)
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Stabilization of magnetic curvature-driven Rayleigh-Taylor instabilities
- 2012
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Ingår i: Journal of Plasma Physics. - : Cambridge University Press (CUP). - 0022-3778 .- 1469-7807. ; 78, s. 93-97
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Tidskriftsartikel (refereegranskat)abstract
- The finite ion Larmor radius (FLR) stabilization of the magnetic curvature-driven Rayleigh Taylor (MCD RT) instability in a low beta plasma with nonzero ion temperature gradient is investigated. Finite electron temperature effects and ion temperature perturbations are incorporated. A new set of nonlinear equations for flute waves with arbitrary wavelengths as compared with the ion Larmor radius in a plasma with curved magnetic field lines is derived. Particular attention is paid to the waves with spatial scales of the order of the ion Larmor radius. In the linear limit, a Fourier transform of these equations yields an improved dispersion relation for flute waves. The dependence of the M CD RT instability growth rate on the equilibrium plasma parameters and the wavelengths is studied. The condition for which the instability cannot be stabilized by the FLR effects is found.
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| 4. |
- Onishchenko, O G, et al.
(författare)
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The magnetic Rayleigh-Taylor instability and flute waves at the ion Larmor radius scales
- 2011
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Ingår i: PHYSICS OF PLASMAS. - : American Institute of Physics. - 1070-664X .- 1089-7674. ; 18:2, s. 022106-
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Tidskriftsartikel (refereegranskat)abstract
- The theory of flute waves (with arbitrary spatial scales compared to the ion Larmor radius) driven by the Rayleigh-Taylor instability (RTI) is developed. Both the kinetic and hydrodynamic models are considered. In this way we have extended the previous analysis of RTI carried out in the long wavelength limit. It is found that complete finite ion Larmor radius stabilization is absent when the ion diamagnetic velocity attains the ion gravitation drift velocity. The hydrodynamic approach allowed us to deduce a new set of nonlinear equations for flute waves with arbitrary spatial scales. It is shown that the previously deduced equations are inadequate when the wavelength becomes of the order of the ion Larmor radius. In the linear limit a Fourier transform of these equations yields the dispersion relation which in the so-called Pade approximation corresponds to the results of the fully kinetic treatment. The development of such a theory gives us enough grounds for an adequate description of the RTI stabilization by the finite ion Larmor radius effect.
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| 5. |
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| 6. |
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| 7. |
- Shukla, P K, et al.
(författare)
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Acoustic gravity tornadoes in the atmosphere
- 2012
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Ingår i: Physica Scripta. - : Institute of Physics. - 0031-8949 .- 1402-4896. ; 86:6
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that three-dimensional (3D) acoustic gravity waves (AGWs) in the atmosphere can appear in the form of acoustic gravity tornadoes (AGTs) characterized by twisted density structures or density ropes carrying orbital angular momentum. For our purposes, we use a previously obtained 3D wave equation for AGWs, and show that this equation in the paraxial approximation admits solutions in the form of Laguerre-Gauss acoustic gravity vortex beams or AGTs/AG whirls with twisted density structures supporting the dynamics of the AGTs.
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| 8. |
- Shukla, P.K., et al.
(författare)
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Alfvenic shock waves in a collisional magnetoplasma
- 2011
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Ingår i: Physics Letters A. - : Elsevier Science B.V., Amsterdam.. - 0375-9601 .- 1873-2429. ; 375:24, s. 2371-2373
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Tidskriftsartikel (refereegranskat)abstract
- Compressional Alfvenic shock waves in a cold collisional magnetoplasma are investigated. For this purpose, we use the hydrodynamic equations and Faradays law to derive the governing nonlinear equations for the compressional Alfven waves. It is shown that the latter can appear in the form of Alfvenic shock waves.
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| 9. |
- Shukla, P.K., et al.
(författare)
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Dark and grey compressional dispersive Alfven solitons in plasmas
- 2011
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Ingår i: Physics of Plasmas. - : American Institute of Physics. - 1070-664X .- 1089-7674. ; 18:6, s. 064511-
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Tidskriftsartikel (refereegranskat)abstract
- The amplitude modulation of compressional dispersive Alfven (CDA) waves in a low-beta plasma is considered. It is shown that the dynamics of modulated CDA waves is governed by a cubic nonlinear Schrodinger equation, which depicts the formation of a dark/grey envelope CDA soliton.
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| 10. |
- Shukla, P. K., et al.
(författare)
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Dispersion relations for electromagnetic waves in a dense magnetized plasma
- 2008
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Ingår i: Journal of Plasma Physics. - Cambridge UK : Cambridge University Press. - 0022-3778 .- 1469-7807. ; 74:Part 6, s. 719-723
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Dispersion relations for elliptically polarized extraordinary is well as linearly polarized ordinary, electromagnetic waves propagating across an external magnetic hold in a dense magnetoplasma are derived, taking into account the combined effects of the quantum electrodynamical (QED) field, as well as the quantum forces associated with the Bohm potential and the magnetization energy, of Me electrons due to the electron-1/2 spin effect. QED (vacuum polarization) effects, which contribute to the nonlinear electron current density, modify the refractive index. Our results concern the propagation characteristics of perpendicularly propagating high-frequency electromagnetic waves in dense astrophysical objects (e.g. neutron sows and magnetars), as well as the next-generation intense laser-solid density plasma interaction experiments and quantum free-electron laser schemes.
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