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Статті в журналах з теми "Plasma Dispersion effect"

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Автор: Grafiati

Опубліковано: 6 вересня 2023

Оновлено: 7 вересня 2023

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1

KNELLER, M., and R. SCHLICKEISER. "Mode limitation and mode completion in collisionless plasmas." Journal of Plasma Physics 60, no. 1 (August 1998): 193–202. http://dx.doi.org/10.1017/s0022377898006485.

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The relativistically correct solution of the dispersion relation of linear plasma waves in an isotropic unmagnetized equilibrium electron plasma leads to two new effects unknown from the nonrelativistic dispersion theory. First, the number of damped subluminal modes is limited to a few (mode-limitation effect); secondly, for relativistic plasma temperatures the few individual modes complement each other in the sense that the dispersion relations ωR=ωR(k) continuously match each other (mode-completion effect). The second effect does not occur at nonrelativistic temperatures.

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2

Ribeiro, Ana I., Martina Modic, Uros Cvelbar, Gheorghe Dinescu, Bogdana Mitu, Anton Nikiforov, Christophe Leys, et al. "Effect of Dispersion Solvent on the Deposition of PVP-Silver Nanoparticles onto DBD Plasma-Treated Polyamide 6,6 Fabric and Its Antimicrobial Efficiency." Nanomaterials 10, no. 4 (March 26, 2020): 607. http://dx.doi.org/10.3390/nano10040607.

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Polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) dispersed in ethanol, water and water/alginate were used to functionalize untreated and dielectric barrier discharge (DBD) plasma-treated polyamide 6,6 fabric (PA66). The PVP-AgNPs dispersions were deposited onto PA66 by spray and exhaustion methods. The exhaustion method showed a higher amount of deposited AgNPs. Water and water-alginate dispersions presented similar results. Ethanol amphiphilic character showed more affinity to AgNPs and PA66 fabric, allowing better uniform surface distribution of nanoparticles. Antimicrobial effect in E. coli showed good results in all the samples obtained by exhaustion method but using spray method only the DBD plasma treated samples displayed antimicrobial activity (log reduction of 5). Despite the better distribution achieved using ethanol as a solvent, water dispersion samples with DBD plasma treatment displayed better antimicrobial activity against S. aureus bacteria in both exhaustion (log reduction of 1.9) and spray (methods log reduction of 1.6) due to the different oxidation states of PA66 surface interacting with PVP-AgNPs, as demonstrated by X-ray Photoelectron Spectroscopy (XPS) analysis. Spray method using the water-suspended PVP-AgNPs onto DBD plasma-treated samples is much faster, less agglomerating and uses 10 times less PVP-AgNPs dispersion than the exhaustion method to obtain an antimicrobial effect in both S. aureus and E. coli.

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3

SHOKRI, B. "The effect of quantum oscillation in plasmas." Journal of Plasma Physics 67, no. 5 (June 2002): 329–37. http://dx.doi.org/10.1017/s0022377802001666.

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Making use of the dielectric permitivitty of a solid state plasma obtained from linearizing a quantum hydrodynamic equation, volume and surface waves in cold semibounded plasma-like media and thin layers of solid state plasmas are investigated in the presence and absence of an external magnetic field. It is shown that quantum oscillation of free charged particles and its spatial dispersion even in cold plasmas lead to new spectra of collective oscillations. Furthermore, a new volume ion-acoustic-type wave is obtained with a quadratic dependence on the wavenumber in the long-wavelength limit. Moreover, it is shown that quantum oscillation affects the surface wave spectrum and extends it to a wider frequency region.

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4

Ataei, Elahe, Mehdi Sharifian, and Najmeh Zare Bidoki. "Magnetized plasma photonic crystals band gap." Journal of Plasma Physics 80, no. 4 (April 9, 2014): 581–92. http://dx.doi.org/10.1017/s0022377814000105.

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In this paper, the effect of the magnetic field on one-dimensional plasma photonic crystal band gaps is studied. The one-dimensional fourfold plasma photonic crystal is applied that contains four periodic layers of different materials, namely plasma1–MgF2–plasma2–glass in one unit cell. Based on the principle of Kronig–Penney's model, dispersion relation for such a structure is obtained. The equations for effective dielectric functions of these two modes are theoretically deduced, and dispersion relations for transverse electric (TE) and transverse magnetic (TM) waves are calculated. At first, the main band gap width increases by applying the exterior magnetic field. Subsequently, the frequency region of this main band gap transfers completely toward higher frequencies. There is a particular upper limit for the magnitude of the magnetic field above which increasing the exterior magnetic field strength doesn't have any significant influence on the dispersion function behavior. (With an increase in incident angle up to θ1= 66°, the width of photonic band gap (PBG) changes for both TM/TE polarization.) With an increase in incident angle up to θ1= 66°, the width of PBG decreases for TM polarization and the width of PBG increases for TE polarization, but it increases with further increasing of the incident angle from θ1= 66° to 89° for both TE- and TM-polarizations. Also, it has been observed that the width of the photonic band gaps changes rapidly by relative difference of the two-plasma frequency. Results show the existence of several photonic band gaps that their frequency and dispersion magnitude can be controlled by the exterior magnetic field, incident angle, and two plasma frequencies. The result of this research would provide theoretical instructions for designing filters, microcavities, fibers, etc.

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5

Cheng, Li-Hong, and Ju-Kui Xue. "Laser-electron interaction in plasma channel with dispersion effect." Journal of Physics: Conference Series 875 (July 2017): 022038. http://dx.doi.org/10.1088/1742-6596/875/3/022038.

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6

Pinhas, Hadar, Omer Wagner, Yossef Danan, Meir Danino, Zeev Zalevsky, and Moshe Sinvani. "Plasma dispersion effect based super-resolved imaging in silicon." Optics Express 26, no. 19 (September 14, 2018): 25370. http://dx.doi.org/10.1364/oe.26.025370.

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7

Zhu, Qi, Xin Ma, Xing Cao, Bin-Bin Ni, Zheng Xiang, Song Fu, Xu-Dong Gu, and Yuan-Nong Zhang. "Assessment of applicability of cold plasma dispersion relation of slot region hiss based on Van Allen Probes observations." Acta Physica Sinica 71, no. 5 (2022): 051101. http://dx.doi.org/10.7498/aps.71.20211671.

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Electron scattering caused by plasmapheric hiss is the dominant mechanism that is responsible for the formation of slot region (1.8 ≤ <i>L</i> ≤ 3) between the Earth’s inner and outer radiation belts. The cold plasma dispersion relation of plasmaspheric hiss is widely used to quantify its scattering effect on energetic electrons. However, the existence of hot plasmas in the realistic magnetospheric environment will modify the dispersion properties of plasmaspheric hiss. According to Van Allen Probes observations, we select all hiss events in the slot region and compare the observed hiss wave amplitudes with the converted hiss wave amplitudes deduced from cold plasma dispersion relation and electric field observations, and then study the dependence of the applicability of cold plasma dispersion relation of slot region hiss on spatial position and geomagnetic activity. The results show that the cold plasma approximation tends to overestimate the amplitude of slot region hiss. The difference between the observed amplitude and the converted hiss wave amplitude has a strong day night asymmetry. However, it shows a slight dependence on the level of geomagnetic activities. In addition, we find that the converted wave magnetic field intensity is significantly lower (higher) than the observed magnetic field intensity at lower frequencies (higher frequencies), which indicates that the cold plasma approximation generally overestimates (underestimates) the scattering effects of hiss waves on the lower (higher) energy electrons in the slot region. Our study confirms that the application scope of the cold plasma dispersion relation of slot hiss has strong spatial and frequency limitations, which is of great importance in deepening our understanding of the dynamic evolution of electrons in the slot region.

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8

MENGESHA, ALEMAYEHU, and S. B. TESSEMA. "Effect of viscosity on propagation of MHD waves in astrophysical plasma." Journal of Plasma Physics 79, no. 5 (January 25, 2013): 535–44. http://dx.doi.org/10.1017/s0022377813000020.

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AbstractWe determine the general dispersion relation for the propagation of magnetohydrodynamic (MHD) waves in an astrophysical plasma by considering the effect of viscosity with an anisotropic pressure tensor. Basic MHD equations have been derived and linearized by the method of perturbation to develop the general form of the dispersion relation equation. Our result indicates that an astrophysical plasma with an anisotropic pressure tensor is stable in the presence of viscosity and a strong magnetic field at considerable wavelength.

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9

Siddique, M., M. Jamil, A. Rasheed, F. Areeb, Asif Javed, and P. Sumera. "Impact of Relativistic Electron Beam on Hole Acoustic Instability in Quantum Semiconductor Plasmas." Zeitschrift für Naturforschung A 73, no. 2 (January 26, 2018): 135–41. http://dx.doi.org/10.1515/zna-2017-0275.

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AbstractWe studied the influence of the classical relativistic beam of electrons on the hole acoustic wave (HAW) instability exciting in the semiconductor quantum plasmas. We conducted this study by using the quantum-hydrodynamic model of dense plasmas, incorporating the quantum effects of semiconductor plasma species which include degeneracy pressure, exchange-correlation potential and Bohm potential. Analysis of the quantum characteristics of semiconductor plasma species along with relativistic effect of beam electrons on the dispersion relation of the HAW is given in detail qualitatively and quantitatively by plotting them numerically. It is worth mentioning that the relativistic electron beam (REB) stabilises the HAWs exciting in semiconductor (GaAs) degenerate plasma.

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10

CHISTYAKOV, M. V., and D. A. RUMYANTSEV. "COMPTON EFFECT IN STRONGLY MAGNETIZED PLASMA." International Journal of Modern Physics A 24, no. 20n21 (August 20, 2009): 3995–4008. http://dx.doi.org/10.1142/s0217751x09043018.

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The process of Compton scattering γe± → γe± in strongly magnetized hot and cold electron–positron plasma is considered. The analytical expressions for the partial cross-sections in rarefied plasma and the simple expressions for the photon absorption rates in degenerate plasma are obtained. The numerical estimations of the absorption rates for various scattering channels are presented taking into account of the photon dispersion and wave function renormalization in strong magnetic field and plasma. The comparison of the scattering absorption rate with photon splitting probability shows the existence of plasma parameters range where these values are comparable with each other.

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11

Paul, SN, S. Chakraborty, and A. Roy Chowdhury. "Effect of Streaming Electrons on the Propagation of Electromagnetic Waves in a Magnetised Relativistic Plasma." Australian Journal of Physics 47, no. 1 (1994): 59. http://dx.doi.org/10.1071/ph940059.

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Expressions for the first- and third-order dispersion relations have been derived for circularly polarised waves in a magnetised relativistic plasma containing electron streams. From the first-order dispersion relations it is seen that the waves are split into three parts, one of which is reflected causing the formation of standing waves in the streaming plasma. From the third-order dispersion relations, the expression for the shifts of wave number has been obtained. It is observed that the streaming of electrons has a significant contribution to the wave-number shift of the electromagnetic waves.

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12

Luo, Qinghuan. "Propagation Effects on Pulsar Radio Emission." Publications of the Astronomical Society of Australia 18, no. 4 (2001): 400–406. http://dx.doi.org/10.1071/as01050.

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AbstractPropagation effects on radio emission within the pulsar magnetosphere are discussed. Widely accepted pulsar models assume that a pulsar magnetosphere is populated with relativistic pair plasmas produced through electron–positron cascades by accelerated primary particles above the polar cap. Any radio emission produced well inside the light cylinder (the radius at which the rotation speed equals c) must propagate through the magnetospheric plasma and be subject to plasma dispersion effects such as refraction and absorption. The observed pulse profiles should contain some features that reflect the influence of the intervening plasma. I discuss particularly the absorption effect due to cyclotron resonance and its possible observational consequences.

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13

Agapova, D. V., S. A. Belov, N. E. Molevich, and D. I. Zavershinskii. "FAST AND SLOW MHD WAVES IN THERMALLY ACTIVE PLASMA SLAB." Vestnik of Samara University. Natural Science Series 28, no. 1-2 (December 29, 2022): 120–27. http://dx.doi.org/10.18287/2541-7525-2022-28-1-2-120-127.

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We considered the combined influence of the thermal activity and the magnetic structuring on properties of the compressional magnetohydrodynamic (MHD) waves. To model MHD waves we use the single magnetic slab geometry. To derive dispersion equations for the symmetric (sausage) and anti-symmetric (kink) waves, we apply the assumption of strong magnetic structuring. In our calculations we use parameters corresponding to the highly magnetized coronal loop. The thermal activity leads to the changes in the phase velocity and in the wave increment/decrement. We show that the spatial scales where the dispersion effects caused by the thermal activity is most pronounced are longer than the geometry dispersion spatial scale. The thermal activity and wave-guide geometry have comparable effect on the slow-waves phase velocity dispersion. However, the main source of the phase velocity dispersion for the fast MHD waves remains the wave-guide geometry. We also show that the damping of slow MHD waves caused by the thermal activity is greater than the damping of fast MHD waves.

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14

Aliev, Yu M., and M. Krämer. "Effect of the plasma density gradient on helicon mode dispersion." Physica Scripta 79, no. 3 (March 2009): 035502. http://dx.doi.org/10.1088/0031-8949/79/03/035502.

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15

Takenaka, Mitsuru, and Shinichi Takagi. "Strain Engineering of Plasma Dispersion Effect for SiGe Optical Modulators." IEEE Journal of Quantum Electronics 48, no. 1 (January 2012): 8–16. http://dx.doi.org/10.1109/jqe.2011.2176104.

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16

Gao, Yong, Guo-zheng Li, Xi-ding Liu, En-ke Liu, Xiang-jiu Zhang, Xue-kun Lu, and Xun Wang. "SiGe Optical Waveguide Modulators Based on the Plasma Dispersion Effect." Chinese Physics Letters 13, no. 3 (March 1996): 189–91. http://dx.doi.org/10.1088/0256-307x/13/3/009.

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17

Kumar, Nagendra, Krishna M. Srivastava, and Vinod Kumar. "Effect of large Larmor radius on the stability of an infinitely conducting inhomogeneous plasma." Journal of Plasma Physics 48, no. 2 (October 1992): 245–60. http://dx.doi.org/10.1017/s0022377800016536.

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The effect of a large Larmor radius on the stability of an infinitely conducting infinitely extended inhomogeneous plasma with two-dimensional magnetic field has been studied. A dispersion relation is obtained for the homogeneous system, and it is found that it is stable and MHD waves propagate. For an inhomogeneous plasma, a dispersion relation is also obtained and discussed for disturbances propagating transverse to inhomogeneity in (a) a cold plasma and (b) an incompressible plasma. It is found that the inhomogeneous system is unstable in both the cases, in agreement with the results of Lee and Roberts. The values of ωr and ωi are computed numerically, and the variations of ωi>0 and the corresponding ωr with the large-Larmor-radius parameter are shown graphically.

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18

PAKZAD, HAMID REZA, and MOULOUD TRIBECHE. "Effect of superthermal electrons on dust-acoustic shock waves in coupled dusty plasmas." Journal of Plasma Physics 79, no. 1 (November 12, 2012): 97–103. http://dx.doi.org/10.1017/s0022377812000797.

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AbstractNonlinear dust-acoustic (DA) shock waves in coupled dusty plasmas with negative dust grains and kappa-distributed electrons are discussed. Using a generalized hydrodynamic model, the dispersion relation and the Korteweg–de Vries-Burger (KdVB) equation for low-frequency DA modes in a strongly coupled dusty plasma are derived. The dependence of shock waves on various plasma parameters is then explored. A solitonic profile may be converted into a shock structure when correlation among dust particles becomes stronger. The amplitude as well as the steepness of shock waves increases with increasing the value of the spectral index k.

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19

Oumbarek Espinos, Driss, Amin Ghaith, Thomas André, Charles Kitégi, Mourad Sebdaoui, Alexandre Loulergue, Fabrice Marteau, et al. "Skew Quadrupole Effect of Laser Plasma Electron Beam Transport." Applied Sciences 9, no. 12 (June 14, 2019): 2447. http://dx.doi.org/10.3390/app9122447.

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Laser plasma acceleration (LPA) capable of providing femtosecond and GeV electron beams in cm scale distances brings a high interest for different applications, such as free electron laser and future colliders. Nevertheless, LPA high divergence and energy spread require an initial strong focus to mitigate the chromatic effects. The reliability, in particular with the pointing fluctuations, sets a real challenge for the control of the dispersion along the electron beam transport. We examine here how the magnetic defects of the first strong quadrupoles, in particular, the skew terms, can affect the brightness of the transported electron beam, in the case of the COXINEL transport line, designed for manipulating the electron beam properties for a free electron laser application. We also show that the higher the initial beam divergence, the larger the degradation. Experimentally, after having implemented a beam pointing alignment compensation method enabling us to adjust the position and dispersion independently, we demonstrate that the presence of non-negligible skew quadrupolar components induces a transversal spread and tilt of the beam, leading to an emittance growth and brightness reduction. We are able to reproduce the measurements with beam transport simulations using the measured electron beam parameters.

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20

SHUKLA, P. K., and L. STENFLO. "Dispersion relations for electromagnetic waves in a dense magnetized plasma." Journal of Plasma Physics 74, no. 6 (December 2008): 719–23. http://dx.doi.org/10.1017/s0022377808007344.

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AbstractDispersion relations for elliptically polarized extraordinary as well as linearly polarized ordinary electromagnetic waves propagating across an external magnetic field 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 the electrons due to the electron-1/2 spin effect. The 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 stars 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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21

Abdul Rauf, I. Zeba, and Muhammad Saqlain. "Modified Dust-Lower-Hybrid Waves in Quantum Plasma." Scientific Inquiry and Review 2, no. 2 (April 30, 2018): 11–21. http://dx.doi.org/10.32350/22/020202.

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Dust-lower-hybrid waves in quantum plasma have been studied. The dispersion relation of the dust-lower-hybrid wave has been examined using the quantum hydrodynamic model of plasma in an ultra-cold Fermi dusty plasma in the presence of a uniform external magnetic field. Graphical analysis shows that the electron Fermi temperature effect and the quantum corrections give rise to significant effects on the dust-lower-hybrid wave of the magnetized quantum dusty plasma.

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22

Robinson, P. A. "Electron cyclotron waves: dispersion and accessibility conditions in isotropic and anisotropic plasmas." Journal of Plasma Physics 35, no. 2 (April 1986): 187–207. http://dx.doi.org/10.1017/s0022377800011272.

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Dispersion and accessibility conditions for electron cyclotron waves are investigated for arbitrary weakly relativistic plasmas and for specific isotropic and loss-cone distributions. The transition between the cold plasma and vacuum dispersion relations is investigated as a function of temperature and density. The behaviour of mode structure (including mode coupling), cut-offs and resonances are also examined. Generalizations are obtained of earlier results which indicate that access by extraordinary waves to regions nearthe cyclotron layer from the low-field side is easier in weakly relativistic plasmas than predicted by cold plasma theory because of a reduction in the cut-off frequency of the fast extraordinary mode. This effect is found to be more pronounced in loss-cone distributions than in isotropic distributions, permitting access at temperatures considerably lower than those predicted in the isotropic case. Extra loss-cone modes are found to appear near the cyclotron frequency in loss-cone plasmas which also exhibit instabilities near the cyclotron harmonics.

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23

Gao, Y., X. J. Zhang, G. Z. Li, X. D. Liu, E. K. Liu, X. K. Lu, J. H. Hu, and X. Wang. "SiGe/Si bifurcation optical active switch based on plasma dispersion effect." Electronics Letters 31, no. 20 (September 28, 1995): 1740–41. http://dx.doi.org/10.1049/el:19951204.

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24

Lim, C. G. "Plasma dispersion effect in heavily doped antimony-based passive optical waveguides." Applied Physics Letters 92, no. 20 (May 19, 2008): 203508. http://dx.doi.org/10.1063/1.2936298.

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25

Treyz, G. V., P. G. May, and Jean‐Marc Halbout. "Silicon Mach–Zehnder waveguide interferometers based on the plasma dispersion effect." Applied Physics Letters 59, no. 7 (August 12, 1991): 771–73. http://dx.doi.org/10.1063/1.105338.

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26

Coppola, Giuseppe, Andrea Irace, Giovanni Breglio, and Antonello Cutolo. "All-silicon mode-mixing router based on the plasma-dispersion effect." Journal of Optics A: Pure and Applied Optics 3, no. 5 (July 12, 2001): 346–54. http://dx.doi.org/10.1088/1464-4258/3/5/306.

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27

Almeida, Vilson R., Qianfan Xu, and Michal Lipson. "Ultrafast integrated semiconductor optical modulator based on the plasma-dispersion effect." Optics Letters 30, no. 18 (September 15, 2005): 2403. http://dx.doi.org/10.1364/ol.30.002403.

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28

ZHANG, Wenyuan, Haojun XU, Binbin PEI, Xiaolong WEI, Pei FENG, and Lin ZHANG. "An electromagnetic wave attenuation superposition structure for thin-layer plasma." Plasma Science and Technology 24, no. 2 (February 1, 2022): 025504. http://dx.doi.org/10.1088/2058-6272/ac4a28.

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Анотація:

Abstract This work proposes a new plasma super-phase gradient metasurfaces (PS-PGMs) structure, owing to the limitations of the thin-layer plasma for electromagnetic wave attenuation. Based on the cross-shaped surface unit configuration, we have designed the X-band absorbing structure through the dispersion control method. By setting up the Drude dispersion model in the computer simulation technology, the designed phase gradient metasurfaces structure is superposed over the plasma, and the PS-PGMs structure is constructed. The electromagnetic scattering characteristics of the new structure have been simulated, and the reflectance measurement has been carried out to verify the absorbing effect. The results demonstrate that the attenuation effect of the new structure is superior to that of the pure plasma structure, which invokes an improved attenuation effect from the thin layer plasma, thus enhancing the feasibility of applying the plasma stealth technology to the local stealth of the strong scattering part of a combat aircraft.

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29

Prialnik, Dina, Aharon Eviatar, and Alexander I. Ershkovich. "The effect of plasma compressibility on the Kelvin-Helmholtz instability." Journal of Plasma Physics 35, no. 2 (April 1986): 209–18. http://dx.doi.org/10.1017/s0022377800011284.

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The Kelvin-Helmholtz (KH) instability of a tangential discontinuity between two compressible plasmas in relative motion is investigated, by solving the dispersion equation for two cases. In the first, neutrals are excluded; in the second, collisions between neutrals and ions are introduced in the form of a drag force in the momentum equation. The velocity of neutrals is assumed to be perpendicular to the interface. In both cases the growth rate of the KH instability is obtained as a function of the density jump between the plasmas. Although it has often been remarked that compressibility should, in general, stabilize a plasma, it is found that this ceases to be true when allowance is made for a significant density jump at the interface. Thus, for a large density jump and a large velocity shear, the instability growth rate in a compressible plasma may considerably exceed the growth rate obtained when incompressibility is assumed. Collisions, it is shown, may either stabilize or destabilize a tangential discontinuity, depending on the change in the product of density and collision frequency (pv), as one moves with the neutrals across the interface; when pv decreases, the instability is enhanced (and vice versa).

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30

KUMAR, NAGENDRA, and KRISHNA M. SRIVASTAVA. "The effect of neutral-gas friction on Alfvén surface waves propagating along a plasma–vacuum interface." Journal of Plasma Physics 60, no. 4 (November 1998): 731–42. http://dx.doi.org/10.1017/s0022377898007144.

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Анотація:

The effect of neutral-gas friction on Alfvén surface waves propagating along an infinitely conducting viscous plasma–vacuum interface has been investigated. A dispersion relation is obtained for such waves. For different values of the neutral-gas friction parameter S=νc/ω (where νc is the collisional frequency between two components of the composite plasma), the variations of the real and imaginary parts kr and ki of the wavenumber k with the viscosity parameter vp= μlω/ρ01v2A1 (where μl and ρ01 are the coefficient of viscosity and the density of plasma media 1) are shown graphically. It is concluded that a three-mode structure of Alfvén surface waves results flowing to neutral-gas friction. It is suggested that our results are useful for both laboratory and astrophysical plasmas (e.g. photospheres, chromospheres and cool interstellar clouds).

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31

TAUTZ, R. C., and J. I. SAKAI. "On the effect of baryon loading in magnetized counterstreaming plasmas. I. Analytical investigation." Journal of Plasma Physics 74, no. 1 (February 2008): 79–90. http://dx.doi.org/10.1017/s0022377807006563.

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Анотація:

AbstractAssuming a non-relativistic three species electron–positron–ion plasma, the counterstreaming instability is investigated for waves propagating parallel and perpendicular to a homogeneous background magnetic field. From the exact linear dispersion relations, it is shown analytically how the growth rates change with increasing baryon loading, revealing new characteristics that cannot be found either for an unmagnetized plasma involving three particle species or for a plasma with only two particle species.

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32

STOCKEM, A., M. LAZAR, P. K. SHUKLA, and A. SMOLYAKOV. "A comparative study of the filamentation and Weibel instabilities and their cumulative effect. II. Weakly relativistic beams." Journal of Plasma Physics 75, no. 4 (August 2009): 529–43. http://dx.doi.org/10.1017/s002237780800768x.

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AbstractCounterstreaming plasma systems with intrinsic temperature anisotropies are unstable against the excitation of Weibel-type instabilities, namely, filamentation and Weibel instabilities, and their cumulative effect. Here, the analysis is extended to counterstreaming plasmas with weakly relativistic bulk velocities, while the thermal velocities are still considered to be non-relativistic. Such plasma systems are relevant for fusion plasma experiments and the more violent astrophysical phenomena, such as jets in gamma-ray burst sources. Simple analytical forms of the dispersion relations are derived in the limit of a small transverse temperature or a large temperature anisotropy of the beams. The aperiodic growing solutions are plotted systematically for the representative cases chosen in Paper I (Lazar et al. 2009 J. Plasma Phys. 75, in press). In the limit of slow non-relativistic plasma flows, the numerical solutions fit well with those obtained in Paper I, but for weakly relativistic streams an important deviation is found.

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33

Chaudhary, Sandhya, Nilesh Nimje, Nishchhal Yadav, and S. Ghosh. "Drift Modified Longitudinal Electrokinetic Mode in Colloids Laden Semiconductor Quantum Plasmas." Physics Research International 2014 (September 15, 2014): 1–5. http://dx.doi.org/10.1155/2014/634763.

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Dispersion and absorption characteristics of electrokinetic wave in unmagnetised extrinsic semiconductor with streaming carriers are analytically investigated. By using quantum hydrodynamic model, a linear dispersion relation is derived for longitudinal electrokinetic wave in colloids laden semiconductor plasma under slow electrokinetic mode regime. Results indicate that quantum effect through Bohm potential significantly modifies the dispersion and absorption characteristics of electrokinetic wave spectrum. The outcome is hoped to add substantially to the present knowledge of wave spectrum of longitudinal electrokinetic wave in colloids laden quantum semiconductor plasma subjected to a dc electric field along the direction of wave propagation.

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34

Mudie, Deanna M., Aaron M. Stewart, Jesus A. Rosales, Nishant Biswas, Molly S. Adam, Adam Smith, Christopher D. Craig, Michael M. Morgen, and David T. Vodak. "Amorphous Solid Dispersion Tablets Overcome Acalabrutinib pH Effect in Dogs." Pharmaceutics 13, no. 4 (April 15, 2021): 557. http://dx.doi.org/10.3390/pharmaceutics13040557.

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Calquence® (crystalline acalabrutinib), a commercially marketed tyrosine kinase inhibitor (TKI), exhibits significantly reduced oral exposure when taken with acid-reducing agents (ARAs) due to the low solubility of the weakly basic drug at elevated gastric pH. These drug–drug interactions (DDIs) negatively impact patient treatment and quality of life due to the strict dosing regimens required. In this study, reduced plasma drug exposure at high gastric pH was overcome using a spray-dried amorphous solid dispersion (ASD) comprising 50% acalabrutinib and 50% hydroxypropyl methylcellulose acetate succinate (HPMCAS, H grade) formulated as an immediate-release (IR) tablet. ASD tablets achieved similar area under the plasma drug concentration–time curve (AUC) at low and high gastric pH and outperformed Calquence capsules 2.4-fold at high gastric pH in beagle dogs. In vitro multicompartment dissolution testing conducted a priori to the in vivo study successfully predicted the improved formulation performance. In addition, ASD tablets were 60% smaller than Calquence capsules and demonstrated good laboratory-scale manufacturability, physical stability, and chemical stability. ASD dosage forms are attractive for improving patient compliance and the efficacy of acalabrutinib and other weakly basic drugs that have pH-dependent absorption.

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35

GIRKA, V. O., I. O. GIRKA, and I. V. PAVLENKO. "HF surface cyclotron waves in planar waveguide structures with non-uniform plasma filling." Journal of Plasma Physics 58, no. 1 (July 1997): 31–39. http://dx.doi.org/10.1017/s0022377897005801.

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The effects of dispersion of slow electromagnetic surface waves propagating across an external magnetic field in planar metallic waveguides with dielectric coating and non-uniform plasma filling on the harmonics of the electron cyclotron frequency are studied. The theoretical investigation of the surface modes is carried out using a kinetic description for the plasma particles and a mirror-reflection model for the interaction between particles and plasma boundary. The effect of the transverse plasma density inhomogeneity on the electron surface cyclotron-wave spectrum is investigated.

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36

Azarvand-Hassanfard, B., A. Esfandyari-Kalejahi, and M. Akbari-Moghanjoughi. "Generation of dispersive shock waves in nonextensive plasmas." Canadian Journal of Physics 96, no. 10 (October 2018): 1063–73. http://dx.doi.org/10.1139/cjp-2017-0589.

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In this research we use a generalized hydrodynamic model to numerically investigate the quasi-neutral expansion and compression of an electron–ion plasma with nonextensive electron velocity distribution into or from vacuum. We study the effects of kinematic viscosity and electron–ion collisions on the expansion profile and compare our results to the numerical solutions of the standard Korteweg – de Vries (KdV) equation. It is found that the quasi-neutrality assumption in the hydrodynamic approach in the absence of viscosity and collisions, which leads to elimination of Poisson’s equation, sets the weak dispersion limit and becomes equivalent to the standard weakly dispersive KdV model. In the weak dispersion limit our model, as well as the KdV with small dispersion effect, predicts that a pulse-like initial profile evolves into solitary wave train. We further show that in a plasma expansion different shock profiles, such as purely dispersive, diffusive–dispersive, and dissipative ones, with significantly different characters may form. Finally, the effect of electron nonextensivity on oscillatory shock waves shows that the expansion profile is affected by changes of q-parameter. Our numerical solution is in qualitative agreement with some distinguished experiments showing the possibility of dispersive shock wave formation in rarefied plasma during an expansion into vacuum.

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37

Shoucri, M. "Helicon waves in a cylindrical plasma column." Journal of Plasma Physics 52, no. 3 (December 1994): 465–70. http://dx.doi.org/10.1017/s0022377800027264.

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Helicon waves have been used for efficiently coupling radio-frequency power to plasmas, and are studied for their potential application for low-frequency current drive in tokamks. In this paper the electromagnetic field components and the dispersion relation for azimuthally independent helicon-wave oscillations in a cylindrical plasma column are derived. The coupling of transverse electric TE and transverse magnetic TM modes associated with these oscillations is discussed. The effect of the collisional damping on determining the nature of the TM mode (either surface wave or body wave) is analysed.

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38

Ghaffar, A., M. Umair, Majeed A. S. Alkanhal, and Y. Khan. "Dispersion characteristics of surface plasmon polaritons in a graphene–plasma–graphene waveguide structure." Canadian Journal of Physics 100, no. 2 (February 2022): 123–28. http://dx.doi.org/10.1139/cjp-2019-0642.

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Theoretical investigations are carried out to study surface wave propagation for a graphene parallel-plate waveguide structure filled with isotropic plasma. The extended wave propagation theory is used. The Kobo formula is used to determine graphene conductivity. Maxwell’s equations (differential form) are used to solve the analytical problem. It is concluded that surface wave propagation can be tuned and controlled by tuning the plasma parameters (plasma frequency and collisional frequency) as well as chemical potential and relaxation time of graphene. Furthermore, the effect of plasma frequency and collisional frequency on the wave attenuation is discussed, and the effect of graphene’s chemical potential, plasma frequency, and collisional frequency on propagation length are also analyzed. The normalized field distribution of plasma medium is also studied. These results may lead to potential applications in optical sensing, communication, and plasma-based optical integrated devices in the gigahertz frequency regime.

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39

UPADHYAY, A., V. K. TRIPATHI, A. K. SHARMA, and H. C. PANT. "Asymmetric self-focusing of a laser pulse in plasma." Journal of Plasma Physics 68, no. 1 (July 2002): 75–80. http://dx.doi.org/10.1017/s0022377802001794.

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An intense short-pulse laser propagating through a plasma undergoes self-pulse distortion due to the combined effects of nonlinearity-induced self-focusing and dispersion. The nonlinearity arises as a result of relativistic mass variation. The low-intensity front of the pulse converges mildly, while the high-intensity later portions self-focus strongly. However, at the intensity maxima, the self-focusing effect is masked by the saturation effect of the nonlinear refractive index. The group velocity is also a function of intensity; as a result, the front of the pulse becomes sharpened, while the tail tends to be broadened.

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40

Okada, Toshio, and Winfried Schmidt. "Two-stream and filamentation instabilities for a light ion beam—plasma system." Journal of Plasma Physics 37, no. 3 (June 1987): 373–82. http://dx.doi.org/10.1017/s0022377800012253.

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Electrostatic two-stream and electromagnetic filamentation instabilities for a light ion beam penetrating a plasma are investigated. The dispersion relations of these instabilities including the effect of plasma heating by the ion beam are solved analytically and numerically. Stability conditions are derived for propagation through a plasma. Attention is paid to the finite size effects of beams with small diameters of the order 0·1 cm typical for pinched gas discharges. The results are illustrated by plotting stability boundaries for a 100 keV proton beam propagating through a plasma.

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41

Er, Xinzhong, Jiangchuan Yu, Adam Rogers, Shihang Liu, and Shude Mao. "Bias in apparent dispersion measure due to de-magnification of plasma lensing on background radio sources." Monthly Notices of the Royal Astronomical Society 510, no. 1 (December 3, 2021): 197–204. http://dx.doi.org/10.1093/mnras/stab3441.

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ABSTRACT The effect of ionized gas on the propagation of radio signals is known as plasma lensing. Unlike gravitational lensing, plasma lensing causes both magnification and strong de-magnification effects to background sources. We study the cross-section of plasma lensing for two density profiles, the Gaussian and power-law models. In general, the cross-section increases with the density gradient. Radio sources can be used to measure the free electron density along the line of sight. However, plasma lensing de-magnification causes an underestimate of the electron density. Such a bias increases with the electron density, and can be up to $\sim 15{{\ {\rm per \ cent}}}$ in the high density region. There is a large probability that high density clumps will be missed due to this bias. The magnification of plasma lensing can also change the luminosity function of the background sources. The number density of sources on both the high- and low-luminosity ends can be overestimated due to this biasing effect.

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42

Li, Baojun, Zuimin Jiang, Xiangjiu Zhang, Xun Wang, Jianjun Wan, Guozheng Li, and Enke Liu. "SiGe/Si Mach–Zehnder interferometer modulator based on the plasma dispersion effect." Applied Physics Letters 74, no. 15 (April 12, 1999): 2108–9. http://dx.doi.org/10.1063/1.123771.

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43

Ivanov, S. T., and N. I. Nikolaev. "Magnetic-field effect on wave dispersion in a free semiconductor plasma slab." Journal of Physics D: Applied Physics 32, no. 4 (January 1, 1999): 430–39. http://dx.doi.org/10.1088/0022-3727/32/4/013.

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44

HU, QIANG-LIN, GUI-LAN XIAO, and XIAO-GUANG YU. "Modulational instability of an ultra-intense laser pulse in electron–positron plasmas." Journal of Plasma Physics 79, no. 5 (May 3, 2013): 771–76. http://dx.doi.org/10.1017/s0022377813000482.

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AbstractThis paper investigates the modulational instability of a linearly polarized ultra-intense laser pulse propagating in electron–positron plasmas. Based on the wave equation, which contains vacuum polarization and magnetization effects, the nonlinear dispersion relation and the growth rate of instability are obtained and the effects of plasma number density and laser intensity on the growth rate are analyzed. Numerical results show that if the laser intensity is high enough, the modulational instability growth rate induced by vacuum polarization and magnetization nonlinearity can dominate the modulational instability growth rate induced by the nonlinearity associated with a relativistic effect and ponderomotive force.

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45

Grozev, D., A. Shivarova, and A. D. Boardman. "Envelope solitons of surface waves in a plasma column." Journal of Plasma Physics 38, no. 3 (December 1987): 427–37. http://dx.doi.org/10.1017/s0022377800012691.

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The problem of envelope solitons of surface waves is considered on the basis of results for the nonlinear dispersion relation of the waves in a plasma column. The soliton solutions are derived as particular cases of the general solutions obtained by a universal procedure and expressed in terms of Jacobi elliptic functions. Since the two types of interactions, namely the (ω + ω) – ω and the (ω – ω) + ω interactions (where ω is the frequency of the carrier wave) included in the nonlinear dispersion relation act in opposite ways, existence both of bright and dark solitons is shown to be possible. The effect of the ponderomotive force that in our case is expressed through the contribution of the (ω – ω) + ω interaction leads to the formation of dark solitons. The effect of the losses is also considered.

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46

Safdar, A., A. Mushtaq, S. Usman, and Aman-ur-Rehman. "Magnetosonic waves in ion trapped semiconductor chip plasma with effect of exchange correlation potential and relativistic degeneracy." Physica Scripta 97, no. 2 (January 28, 2022): 025603. http://dx.doi.org/10.1088/1402-4896/ac4c51.

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Abstract The generalized dispersion relation for the propagation of magnetohydrodynamic (MHD) waves in Cd+ ion trapped semiconductor electron-hole-ion plasmas is studied with effect of quantum corrections. The important ingredients of these corrections occurred due to Bohm potential, relativistic degeneracy, exchange-correlation potential and spin magnetization and have significant impact on the dispersion properties of perpendicular and oblique modes of MHD wave. The derived results are numerically analyzed by using the numerical parameters of GaAs, GaSb, GaN, and InP semiconductors plasmas. From the numerical analysis it is observed that for higher number density, the phase speed of magnetosonic wave is larger for the InP semiconductor, while for low number density plasma region, it gives lower values for GaAs semiconductor. Similarly the phase speed of magnetosonic wave for GaAs decreases with applied magnetic field for different regime of number density. Due to exchange-correlation potential it is found that the frequencies of magnetosonic waves are blue-shifted means that it has magnified the phase speed. It is also shown that frequency of oblique MHD wave for GaAs semiconductor plasmas increases (decreases) with number density of electrons (holes). The relativistic degeneracy term (γ) for given number density is numerically calculated (1.00011 ∼ 1.0058) for all the above-mentioned semiconductors and it is observed that due to its mild numerical value it has not significant impact on graphical manipulation. The Alfven speed for above compound semiconductors with B 0 ≤ 104 G is also calculated which are in the permissible range of order 104 cm/s to 107 cm/s. The results are helpful to understand the energy transport in semiconductor plasma in the presence of magnetic field.

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47

MALAV, HARISH, K. P. MAHESHWARI, R. S. MEGHWAL, Y. CHOYAL, and RAKESH SHARMA. "Analytical and numerical investigation of diffraction effects on the nonlinear propagation of ultra-intense few-cycle optical pulses in plasmas." Journal of Plasma Physics 76, no. 2 (October 1, 2009): 209–27. http://dx.doi.org/10.1017/s0022377809990286.

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AbstractThe propagation of intense few-cycle laser beams in plasma media is considered when the quiver velocity of the electron approaches the velocity of light c. The modifications in the spatio-temporal profile of the initial Gaussian beam are found to depend on the combined effect of relativistic plasma frequency and diffraction. The results of the variation of the temporal profile of the envelope at points on the axis as well away from the axis are presented. The results so obtained are compared with those of vacuum propagation. Pulses get broadened and frequency gets chirped as a result of diffraction, phase dispersion and relativistic mass correction. The effect of the plasma on the group velocity dispersion including curvatures of pulse and phase fronts in pulsed Gaussian beam is numerically investigated.

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48

LAZAR, M., A. SMOLYAKOV, R. SCHLICKEISER, and P. K. SHUKLA. "A comparative study of the filamentation and Weibel instabilities and their cumulative effect. I. Non-relativistic theory." Journal of Plasma Physics 75, no. 1 (February 2009): 19–33. http://dx.doi.org/10.1017/s0022377807007015.

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AbstractA comparative study of the electromagnetic instabilities in anisotropic unmagnetized plasmas is undertaken. The instabilities considered are the filamentation and Weibel instability, and their cumulative effect. Dispersion relations are derived and the growth rates are plotted systematically for the representative cases of non-relativistic counterstreaming plasmas with isotropic or anisotropic velocity distributions functions of Maxwellian type. The pure filamentation mode is attenuated by including an isotropic Maxwellian distribution function. Moreover, it is observed that counterstreaming plasmas can be fully stabilized by including bi-Maxellian distributions with a negative thermal anisotropy. This effect is relevant for fusion plasma experiments. Otherwise, for plasma streams with a positive anisotropy the filamentation and Weibel instabilities cumulate leading to a growth rate by orders of magnitude larger than that of a simple filamentation mode. This is noticeable for the quasistatic magnetic field generated in astrophysical sources, and which is expected to saturate at higher values and explain the non-thermal emission observed.

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49

VERMA, M. P., S. K. MISHRA, and M. S. SODHA. "Effect of the inter-grain attractive potential on lattice dynamics in complex plasmas." Journal of Plasma Physics 79, no. 1 (August 20, 2012): 55–64. http://dx.doi.org/10.1017/s0022377812000694.

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AbstractThe dispersion relation for lattice waves in a linear chain of charged particles in a complex plasma has been derived on the basis of a screened inter-grain repulsive potential and an attractive shadow potential 1/r. It is seen that the inclusion of the attractive potential makes a significant difference in the results; the present results are in good agreement with the experiment. The dispersion relations, corresponding to square and hexagonal planar lattices, with vibrations confined to the plane have also been derived.

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50

Kumar, Pardeep, and Sumit Gupta. "On Thermal Convection of a Plasma in Porous Medium." WSEAS TRANSACTIONS ON APPLIED AND THEORETICAL MECHANICS 16 (August 31, 2021): 110–19. http://dx.doi.org/10.37394/232011.2021.16.11.

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The effect of finite Larmor radius of the ions on thermal convection of a plasma is investigated. The case with vertical magnetic field is discussed. Following linear stability theory and normal mode analysis method, the dispersion relation is obtained. It is found that the presence of finite Larmor radius and magnetic field introduces oscillatory modes in the system which were, otherwise, non-existent in their absence. When the instability sets in as stationary convection, finite Larmor radius is found to have a stabilizing effect. Medium permeability has a destabilizing (or stabilizing) effect and the magnetic field has a stabilizing (or destabilizing) effect under certain conditions in the presence of finite Larmor radius effect whereas in the absence of finite Larmor radius effect, the medium permeability and the magnetic field have destabilizing and stabilizing effects, respectively. The sufficient conditions for the non-existence of overstability are also obtained.

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