Wave propagation in strongly coupled quasi-one-dimensional quantum plasma in a magnetic field

1989 ◽  
Vol 28 (1) ◽  
pp. 63-69
Author(s):  
R. O. Genga
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Quantum Plasma ◽  
Strongly Coupled ◽  
One Dimensional

Effect of dust grains on propagation of electromagnetic wave in a cold quantum dusty plasma

2015 ◽  
Vol 81 (2) ◽  
Author(s):  
Punit Kumar ◽  
Abhisek Kumar Singh
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Incident Radiation ◽  
Intense Laser ◽  
Quantum Plasma ◽  
Intense Laser Pulse ◽  
One Dimensional ◽  
Linearly Polarized ◽  
Linearly Polarized Radiation ◽  
Polarized Radiation

A one-dimensional nonlinear theoretical analysis for the interaction of intense laser pulse with high density electron-ion-dust quantum plasma. The linearly polarized radiation propagates in the presence of a constant magnetic field applied perpendicular to both the electric vector and the direction of propagation. Dispersion of the incident radiation and generation of its harmonics are studied.

Vortices in a strongly coupled collisional quantum plasma embedded in an external magnetic field

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chitrita Dasgupta ◽  
Sarit Maitra
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Vortex Motion ◽  
Radial Distance ◽  
Radial Electric Field ◽  
Momentum Equation ◽  
Electron Exchange ◽  
Quantum Plasma ◽  
Strongly Coupled ◽  
Exchange Correlation

Abstract Vortex motion of a cylindrical quantum plasma containing degenerate inertialess electrons and strongly correlated, non-degenerate inertial ions is studied. The electron exchange–correlation and ion–neutral collisional effects are taken into consideration, along with vertical external magnetic field and radial electric field. Considering generalized viscoelastic momentum equation for strongly coupled ions in quasi-crystalline state, variation of different rotational characteristics along radial distance are discussed numerically. Existence of shear rotation is observed near both the core and the periphery of the vortex, which is found to be modified by ion–ion correlation, quantum effects of the degenerate electrons, the ion–neutral collision, as well as by the magnetic field. It is noticed that electron exchange–correlation potential and quantum diffraction play major roles in modifying the rotational characteristics. Vorticity and the rate of increment of enstrophy with respect to radial distance, diminish to zero towards the periphery of the vortex. Also, it is noted that the ion–neutral collision may be responsible for reducing the increment of enstrophy.

scholarly journals Multi-Acquisition and Multi-Dimensional Earth's Field Nuclear Magnetic Resonance Spectroscopy

2021 ◽  
Author(s):  
◽  
Meghan Eileen Halse
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Density Matrix ◽  
Signal Enhancement ◽  
Spin Coupling ◽  
Earth’S Magnetic Field ◽  
Strongly Coupled ◽  
One Dimensional ◽  
Earth's Magnetic Field ◽  
Spin Spin Coupling

<p>In this thesis we investigate the ways in which the sensitivity, resolution and overall performance of an Earth's field NMR system can be improved without significantly compromising its simplicity, portability or affordability. We investigate the limits of the information obtainable using this device and present a range of methods for calculating and analyzing NMR spectroscopy experiments detected in the Earth's magnetic field. We demonstrate significant improvements in the performance of a commercial Earth's field NMR device, the Terranova-MRI, through several apparatus developments. First-order shimming is added to the system in order to counter any local inhomogeneity of the Earth's field. The spectral resolution of the instrument is further improved through the introduction of a field locking system to counter the natural temporal drift in the magnitude of the Earth's magnetic field. External noise interference is reduced through the use of Faraday screening, effectively increasing the signal-to-noise ratio (SNR) performance of the device. We explore three signal enhancement methodologies for optimizing the SNR performance of the system. Prepolarization, with an electromagnet as well as a permanent magnet array, is considered and compared to dynamic nuclear polarization (DNP) and hyperpolarization via optical pumping. We present a detailed theoretical discussion of DNP in low-fields and demonstrate the application of this technique for signal enhancement in EFNMR. An apparatus for performing DNP in the Earth's field is presented and optimized. A density matrix approach to simulating one- and two-dimensional Earth's field NMR experiments is presented. These numerical simulations, along with a perturbation theory approach to calculating one-dimensional EFNMR spectra of tightly coupled heteronuclear systems, are explored and compared to experimental spectra of the tetrahydroborate and ammonium ions. These systems are of particular interest for NMR detected in the Earth's field because they contain strongly coupled nuclei of differing spin, a situation previously unexplored in the literature. Multi-dimensional Earth's field NMR spectroscopy methods, in particular the correlation spectroscopy (COSY) experiment, are implemented and optimized through the use of shimming, field stabilization and noise screening. The 2D COSY spectrum of monofluorobenzene is analyzed and compared to calculated spectra in order to determine the indirect spin-spin coupling constants of this molecule in the Earth's magnetic field. A 2D COSY spectrum of 1,4-difluorobenzene is also presented and compared to simulation. The SNR performance of COSY in the Earth's field is greatly improved through the use of DNP for signal enhancement. A high-quality, 2D COSY EFNMR spectrum with DNP acquired from 2,2,2- trifluoroethanol is presented and compared to simulation. The particular features of this spectrum, which result from the use of DNP for signal enhancement, are discussed with reference to a density matrix simulation and to a one-dimensional spectrum calculated using perturbation theory. The strong indirect spin-spin coupling regime in fields weaker than the Earth's magnetic field is explored through exact calculations and density matrix simulations of a 13C-enriched methyl group. A novel multi-dimensional EFNMR method for observing such spectra is discussed. This experiment allows for the resolution of strongly coupled NMR spectra both in the Earth's magnetic field, in the directly detected domain, and in weaker fields, in the indirectly detected domain. In the final section of this thesis, residual dipolar coupling is observed by EFNMR for the first time in a system of poly-[gamma]-benzyl-L-glutamate (PBLG) in dichloromethane. The form of the EFNMR spectrum of this liquid crystalline system is discussed and compared to equivalent high-field (9.4T) spectra.</p>

scholarly journals Multi-Acquisition and Multi-Dimensional Earth's Field Nuclear Magnetic Resonance Spectroscopy

2021 ◽  
Author(s):  
◽  
Meghan Eileen Halse
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Density Matrix ◽  
Signal Enhancement ◽  
Spin Coupling ◽  
Earth’S Magnetic Field ◽  
Strongly Coupled ◽  
One Dimensional ◽  
Earth's Magnetic Field ◽  
Spin Spin Coupling

<p>In this thesis we investigate the ways in which the sensitivity, resolution and overall performance of an Earth's field NMR system can be improved without significantly compromising its simplicity, portability or affordability. We investigate the limits of the information obtainable using this device and present a range of methods for calculating and analyzing NMR spectroscopy experiments detected in the Earth's magnetic field. We demonstrate significant improvements in the performance of a commercial Earth's field NMR device, the Terranova-MRI, through several apparatus developments. First-order shimming is added to the system in order to counter any local inhomogeneity of the Earth's field. The spectral resolution of the instrument is further improved through the introduction of a field locking system to counter the natural temporal drift in the magnitude of the Earth's magnetic field. External noise interference is reduced through the use of Faraday screening, effectively increasing the signal-to-noise ratio (SNR) performance of the device. We explore three signal enhancement methodologies for optimizing the SNR performance of the system. Prepolarization, with an electromagnet as well as a permanent magnet array, is considered and compared to dynamic nuclear polarization (DNP) and hyperpolarization via optical pumping. We present a detailed theoretical discussion of DNP in low-fields and demonstrate the application of this technique for signal enhancement in EFNMR. An apparatus for performing DNP in the Earth's field is presented and optimized. A density matrix approach to simulating one- and two-dimensional Earth's field NMR experiments is presented. These numerical simulations, along with a perturbation theory approach to calculating one-dimensional EFNMR spectra of tightly coupled heteronuclear systems, are explored and compared to experimental spectra of the tetrahydroborate and ammonium ions. These systems are of particular interest for NMR detected in the Earth's field because they contain strongly coupled nuclei of differing spin, a situation previously unexplored in the literature. Multi-dimensional Earth's field NMR spectroscopy methods, in particular the correlation spectroscopy (COSY) experiment, are implemented and optimized through the use of shimming, field stabilization and noise screening. The 2D COSY spectrum of monofluorobenzene is analyzed and compared to calculated spectra in order to determine the indirect spin-spin coupling constants of this molecule in the Earth's magnetic field. A 2D COSY spectrum of 1,4-difluorobenzene is also presented and compared to simulation. The SNR performance of COSY in the Earth's field is greatly improved through the use of DNP for signal enhancement. A high-quality, 2D COSY EFNMR spectrum with DNP acquired from 2,2,2- trifluoroethanol is presented and compared to simulation. The particular features of this spectrum, which result from the use of DNP for signal enhancement, are discussed with reference to a density matrix simulation and to a one-dimensional spectrum calculated using perturbation theory. The strong indirect spin-spin coupling regime in fields weaker than the Earth's magnetic field is explored through exact calculations and density matrix simulations of a 13C-enriched methyl group. A novel multi-dimensional EFNMR method for observing such spectra is discussed. This experiment allows for the resolution of strongly coupled NMR spectra both in the Earth's magnetic field, in the directly detected domain, and in weaker fields, in the indirectly detected domain. In the final section of this thesis, residual dipolar coupling is observed by EFNMR for the first time in a system of poly-[gamma]-benzyl-L-glutamate (PBLG) in dichloromethane. The form of the EFNMR spectrum of this liquid crystalline system is discussed and compared to equivalent high-field (9.4T) spectra.</p>

Nonlinear dynamics of pulsating detonation wave with two-stage chemical kinetics in the shock-attached frame

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yaroslava E. Poroshyna ◽  
Aleksander I. Lopato ◽  
Pavel S. Utkin
Keyword(s):  
Wave Propagation ◽  
Detonation Wave ◽  
Model Comparison ◽  
Approximation Order ◽  
Transition Regime ◽  
Stage Model ◽  
Two Stage ◽  
One Dimensional ◽  
Kinetics Of ◽  
Detonation Wave Propagation

Abstract The paper contributes to the clarification of the mechanism of one-dimensional pulsating detonation wave propagation for the transition regime with two-scale pulsations. For this purpose, a novel numerical algorithm has been developed for the numerical investigation of the gaseous pulsating detonation wave using the two-stage model of kinetics of chemical reactions in the shock-attached frame. The influence of grid resolution, approximation order and the type of rear boundary conditions on the solution has been studied for four main regimes of detonation wave propagation for this model. Comparison of dynamics of pulsations with results of other authors has been carried out.

scholarly journals Anomalous Anderson localization behavior in gain-loss balanced non-Hermitian systems

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 443-452
Author(s):  
Tianshu Jiang ◽  
Anan Fang ◽  
Zhao-Qing Zhang ◽  
Che Ting Chan
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Waves ◽  
Anderson Localization ◽  
Random Media ◽  
Normal Incidence ◽  
Disordered Media ◽  
One Dimensional ◽  
Gain Loss ◽  
The Waves ◽  
Localization Behavior

AbstractIt has been shown recently that the backscattering of wave propagation in one-dimensional disordered media can be entirely suppressed for normal incidence by adding sample-specific gain and loss components to the medium. Here, we study the Anderson localization behaviors of electromagnetic waves in such gain-loss balanced random non-Hermitian systems when the waves are obliquely incident on the random media. We also study the case of normal incidence when the sample-specific gain-loss profile is slightly altered so that the Anderson localization occurs. Our results show that the Anderson localization in the non-Hermitian system behaves differently from random Hermitian systems in which the backscattering is suppressed.

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