The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Pavel A Andreev - One of the best experts on this subject based on the ideXlab platform.
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kinetic analysis of spin current contribution to spectrum of electromagnetic Waves in spin 1 2 plasma ii dispersion dependencies
Physics of Plasmas, 2017Co-Authors: Pavel A AndreevAbstract:The dielectric permeability tensor for spin polarized plasmas derived in terms of the spin-1/2 quantum kinetic model in six-dimensional phase space obtained in Part I of this work is applied for the study of spectra of high-frequency transverse and transverse-Longitudinal Waves propagating perpendicular to the external magnetic field. Cyclotron Waves are studied in consideration of Waves with the electric field directed parallel to the external magnetic field. It is found that the separate spin evolution modifies the spectrum of cyclotron Waves. These modifications increase with the increase in spin polarization and the number of the cyclotron resonance. Spin dynamics gives a considerable modification of spectra even if the anomalous part of electron magnetic moment is not included in the model. The account of anomalous magnetic moment leads to a fine structure of each cyclotron resonance. So, each cyclotron resonance splits into three Waves. Details of this spectrum and its changes with the change of spi...
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rich eight branch spectrum of the oblique propagating Longitudinal Waves in partially spin polarized electron positron ion plasmas
Physical Review E, 2016Co-Authors: Pavel A Andreev, Z IqbalAbstract:We consider the separate spin evolution of electrons and positrons in electron-positron and electron-positron-ion plasmas. We consider the oblique propagating Longitudinal Waves in these systems. Working in a regime of high-density n(0) ∼ 10(27) cm(-3) and high-magnetic-field B(0)=10(10) G, we report the presence of the spin-electron acoustic Waves and their dispersion dependencies. In electron-positron plasmas, similarly to the electron-ion plasmas, we find one spin-electron acoustic wave (SEAW) at the propagation parallel or perpendicular to the external field and two spin-electron acoustic Waves at the oblique propagation. At the parallel or perpendicular propagation of the Longitudinal Waves in electron-positron-ion plasmas, we find four branches: the Langmuir wave, the positron-acoustic wave, and a pair of Waves having spin nature, they are the SEAW and the wave discovered in this paper, called the spin-electron-positron acoustic wave (SEPAW). At the oblique propagation we find eight Longitudinal Waves: the Langmuir wave, the Trivelpiece--Gould wave, a pair of positron-acoustic Waves, a pair of SEAWs, and a pair of SEPAWs. Thus, for the first time, we report the existence of the second positron-acoustic wave existing at the oblique propagation and the existence of SEPAWs.
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oblique propagation of Longitudinal Waves in magnetized spin 1 2 plasmas independent evolution of spin up and spin down electrons
Annals of Physics, 2015Co-Authors: Pavel A Andreev, L S KuzmenkovAbstract:We consider quantum plasmas of electrons and motionless ions. We describe separate evolution of spin-up and spin-down electrons. We present corresponding set of quantum hydrodynamic equations. We assume that plasmas are placed in an uniform external magnetic field. We account different occupation of spin-up and spin-down quantum states in equilibrium degenerate plasmas. This effect is included via equations of state for pressure of each species of electrons. We study oblique propagation of Longitudinal Waves. We show that instead of two well-known Waves (the Langmuir wave and the Trivelpiece–Gould wave), plasmas reveal four wave solutions. New solutions exist due to both the separate consideration of spin-up and spin-down electrons and different occupation of spin-up and spin-down quantum states in equilibrium state of degenerate plasmas.
L S Kuzmenkov - One of the best experts on this subject based on the ideXlab platform.
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oblique propagation of Longitudinal Waves in magnetized spin 1 2 plasmas independent evolution of spin up and spin down electrons
Annals of Physics, 2015Co-Authors: Pavel A Andreev, L S KuzmenkovAbstract:We consider quantum plasmas of electrons and motionless ions. We describe separate evolution of spin-up and spin-down electrons. We present corresponding set of quantum hydrodynamic equations. We assume that plasmas are placed in an uniform external magnetic field. We account different occupation of spin-up and spin-down quantum states in equilibrium degenerate plasmas. This effect is included via equations of state for pressure of each species of electrons. We study oblique propagation of Longitudinal Waves. We show that instead of two well-known Waves (the Langmuir wave and the Trivelpiece–Gould wave), plasmas reveal four wave solutions. New solutions exist due to both the separate consideration of spin-up and spin-down electrons and different occupation of spin-up and spin-down quantum states in equilibrium state of degenerate plasmas.
Hisamitsu Baba - One of the best experts on this subject based on the ideXlab platform.
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novel ultrasonic bone densitometry based on two Longitudinal Waves significant correlation with pqct measurement values and age related changes in trabecular bone density cortical thickness and elastic modulus of trabecular bone in a normal japanese
Osteoporosis International, 2010Co-Authors: G Iguchi, Takako Tobimatsu, K Takahashi, Takahiko Otani, Kaoru Horii, Isao Mano, I Nagai, Takuo Fujita, Hisamitsu BabaAbstract:Summary A reference database for trabecular bone density, cortical thickness, and elastic modulus of trabecular bone for a novel ultrasonic bone densitometry system (LD-100) based on two Longitudinal Waves (fast and slow) was determined over a wide age range in a normal Japanese population.
Siddhartha Biswas - One of the best experts on this subject based on the ideXlab platform.
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fundamental solution of the steady oscillations equations in porous thermoelastic medium with dual phase lag model
Mechanics of Materials, 2018Co-Authors: Siddhartha Biswas, Nantu SarkarAbstract:Abstract The purpose of this article is to study the propagation of plane Waves in porous thermoelastic medium. The problem is considered in the context of dual-phase-lag model of generalized thermoelasticity. There exists three Longitudinal Waves, namely elastic (E-mode), thermal (T-mode) and volume fraction (V-mode) in addition to transverse Waves which get decoupled from the rest of motion and not affected by thermal and volume fraction fields. The fundamental solution of the system of differential equations in case of steady oscillations in terms of the elementary functions has been constructed. The phase velocity, attenuation coefficient, specific loss and penetration depth of these Waves are computed numerically and presented graphically.
Martinez V Pille - One of the best experts on this subject based on the ideXlab platform.
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first evidence of interaction between Longitudinal and transverse Waves in solar magnetic elements
Astronomy and Astrophysics, 2013Co-Authors: M Stangalini, S K Solanki, R H Camero, Martinez V PilleAbstract:Small-scale magnetic fields are thought to play an important role in the heating of the outer solar atmosphere. By taking advantage of the unprecedented high-spatial and temporal cadence of the Imaging Magnetograph eXperiment (IMaX), the filter vector polarimeter on board the Sunrise balloon-borne observatory, we study the transversal and Longitudinal velocity oscillations in small magnetic elements. The results of this analysis are then compared to magnetohydrodynamic (MHD) simulations, showing excellent agreement. We found buffeting-induced transverse oscillations with velocity amplitudes of the order of 1–2 km s −1 to be common along with Longitudinal oscillations with amplitudes ∼0.4 km s −1 . Moreover, we also found an interaction between transverse oscillations and Longitudinal velocity oscillations, showing a ±90 ◦ phase lag at the frequency at which they exhibit the maximum coherence in the power spectrum. Our results are consistent with the theoretical picture in which MHD Longitudinal Waves are excited inside small magnetic elements as a response of the flux tube to the forcing action of the granular flows.
