Filamentation and collapse of Langmuir waves in a weak magnetic field

1982 ◽  
Vol 28 (1) ◽  
pp. 19-36 ◽  
Author(s):  
P. Rolland ◽  
S. G. Tagare
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Small Angle ◽  
Nonlinear Interaction ◽  
High Frequency ◽  
Weak Magnetic Field ◽  
Low Frequency ◽  
Langmuir Waves ◽  
The Magnetic Field

The filamentation and collapse of Langmuir waves in a weak magnetic field are analysed in two particular cases of low-frequency acoustic perturbations: (i) adiabatic perturbations which correspond to subsonic collapse, and (ii) nonadiabatic perturbations which correspond to supersonic collapse. Here the existence of Langmuir filaments and Langmuir collapse in a weak magnetic field are due to nonlinear interaction of high-frequency Langmuir waves (which make small angle with the external magnetic field) with low-frequency acoustic perturbations along the magnetic field.

scholarly journals ANALYSIS OF HIGH-FREQUENCY C-CORE MAGNETIC FLUX LEAKAGES FOR BONE TUMOR WITH INDUCTION HEATING BY USING MULTI-COIL

2019 ◽  
Author(s):  
Metharak Jokpudsa ◽  
Supawat Kotchapradit ◽  
Chanchai Thongsopa ◽  
Thanaset Thosdeekoraphat
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Tumor Tissue ◽  
Low Frequency ◽  
Heat Energy ◽  
High Frequencies ◽  
Frequency Magnetic Field ◽  
High Frequency Magnetic Field ◽  
The Magnetic Field ◽  
Flux Leakage

High-frequency magnetic field has been developed pervasively. The induction of heat from the magnetic field can help to treat tumor tissue to a certain extent. Normally, treatment by the low-frequency magnetic field needed to be combined with magnetic substances. To assist in the induction of magnetic fields and reduce flux leakage. However, there are studies that have found that high frequencies can cause heat to tumor tissue. In this paper present, a new magnetic application will focus on the analysis of the high-frequency magnetic nickel core with multi-coil. In order to focus the heat energy using a high-frequency magnetic field into the tumor tissue. The magnetic coil was excited by 915 MHz signal and the combination of tissues used are muscle, bone, and tumor. The magnetic power on the heating predicted by the analytical model, the power loss density (2.98e-6 w/m3) was analyzed using the CST microwave studio.

Nonlinear interaction of electron acoustic waves with Langmuir waves in presence of magnetic field in plasmas

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
Manjistha Dutta ◽  
Manoranjan Khan ◽  
Nikhil Chakrabarti
Keyword(s):  
Magnetic Field ◽  
Nonlinear Interaction ◽  
Acoustic Waves ◽  
Low Frequency ◽  
Acoustic Mode ◽  
Magnetized Plasma ◽  
Langmuir Waves ◽  
Coupled Equations ◽  
Electron Acoustic Wave ◽  
Electron Acoustic

Nonlinear interaction between Langmuir waves and Electron Acoustic Wave (EAW) is being studied in a warm magnetized plasma in presence of two intermingled fluids, hot electrons, and cold electrons while ions forming static background. Two-fluid, two-timescale theory is performed to derive modified Zakharov's equations in a magnetized plasma. These coupled equations describe low-frequency response of electron density due to high-frequency electric field along with magnetic field perturbations. Linear analysis shows coupling between acoustic mode, upper hybrid mode, and cyclotron modes. These modes are found to be modified due to the presence of two electron components. These equations are significant in the context of weak and strong turbulence.

Nyquist diagrams for low-frequency oscillations in a non-uniform magnetoplasma

1968 ◽  
Vol 2 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Bruno Bertotti ◽  
Aldo Nocentini
Keyword(s):  
Magnetic Field ◽  
Dispersion Relation ◽  
External Magnetic Field ◽  
Temperature Gradient ◽  
Low Frequency ◽  
Larmor Radius ◽  
Low Density ◽  
Langmuir Waves ◽  
Local Dispersion ◽  
Low Frequency Oscillations

A modification of the Penrose criterion is applied to the local dispersion relation for low-frequency, electrostatic instabilities in a low-density, slightly inhomogeneous magnetoplasma. The Nyquist diagrams obtained can be classified according to their behaviour near the origin; this is sufficient in some cases to conclude that the equilibrium is unstable. With this method, in the limit of negligible ion Larmor radius, we find that the Langmuir waves propagating in a direction orthogonal to the external magnetic field are driven unstable by a temperature gradient.

Tunable Microwave Composites Containing Ferromagnetic Microwires

2009 ◽  
Vol 1223 ◽  
Author(s):  
Mihail Ipatov ◽  
Larissa Panina ◽  
Gloria R. Aranda ◽  
Valentina Zhukova ◽  
Arcady Zhukov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Field Dependence ◽  
High Frequency ◽  
Free Space ◽  
Effective Permittivity ◽  
Reflection Spectra ◽  
Single Wire ◽  
Amorphous Wires ◽  
The Magnetic Field

ABSTRACTThe effect of the external magnetic field on the dispersion of the effective permittivity in arrays of parallel CoFe-based amorphous wires is demonstrated by measuring S-parameters in free space in the frequency band of 0.9-17 GHz. The magnetic field is applied along the wires sensitively changing their magnetization and high frequency impedance. Based on the measurements of magneto-impedance in a single wire and transmission/reflection spectra of composites in free space, we show the correlation between magneto-impedance and the field dependence of the effective permittivity.

Effect of Ship's Motion on Wave-Generated Magnetic Field in Marine Magnetic Survey

2013 ◽  
Vol 380-384 ◽  
pp. 228-231
Author(s):  
Xing Le Zhu ◽  
Chang Han Xiao ◽  
Zhen Ning Yao
Keyword(s):  
Magnetic Field ◽  
Linear Relationship ◽  
High Frequency ◽  
Low Frequency ◽  
Ocean Waves ◽  
Magnetic Survey ◽  
Noise Elimination ◽  
The Waves ◽  
Magnetization Field ◽  
The Magnetic Field

The survey ship would be interfered by wave-generated magnetic field in marine survey. The waves magnetic field is difficult to eliminate because it is the signal in low frequency like ships magnetization field. When survey ship sails, the frequency of waves magnetic field would change. It was found that the frequency has a linear relationship with ships speed and varies in sine or cosine with the angle between ships and waves directions. Ocean waves PSD would be compressed and strong noise of low frequency in narrowband turns up when ship sails in the same direction of waves. The frequency band of PSD would be broadened and small interference occurs while ships direction is opposite. A conclusion can be drawn that survey ship should sail reversely with ocean waves in marine magnetic survey, so the magnetic field induced by ocean waves would extend to high frequency and it is better for noise elimination.

Diamagnetic Levitation for Passive Tilt Sensors

2007 ◽  
Vol 998 ◽  
Author(s):  
Lihong Jiao ◽  
Martin Winistöerfer
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
External Field ◽  
Opposite Direction ◽  
Weak Magnetic Field ◽  
Magnetic Force ◽  
Diamagnetic Susceptibility ◽  
Diamagnetic Levitation ◽  
Tilt Sensors ◽  
The Magnetic Field

ABSTRACTWhen diamagnetic materials are exposed to an external magnetic field, a weak magnetic field in the opposite direction to the external field is induced and a magnetic force is generated causing diamagnetic materials to be expelled from the external magnetic field. The magnitude of the force increases with increase of the magnitude of diamagnetic susceptibility, χm. In this study, the levitation of graphite in the magnetic field was investigated.

PEMANFAATAN RADIASI ENERGI TEGANGAN 150 KV UNTUK LAMPU LED PENERANGAN JALAN

Jurnal Teknik ◽  
2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Mauludi Manfaluthy
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
High Voltage ◽  
Low Frequency ◽  
Energy Utilization ◽  
World Health ◽  
Electromagnetic Signals ◽  
Health Organization ◽  
The Magnetic Field ◽  
Low Frequency Waves

WHO (World Health Organization) concludes that not much effect is caused by electric field up to 20 kV / m in humans. WHO standard also mentions that humans will not be affected by the magnetic field under  100 micro tesla and that the electric field will affect the human body with a maximum standard of 5,000 volts per meter. In this study did not discuss about the effect of high voltage radiation SUTT (High Voltage Air Channel) with human health. The research will focus on energy utilization of SUTT radiation. The combination of electric field and magnetic field on SUTT (70-150KV) can generate electromagnetic (EM) and radiation waves, which are expected to be converted to turn on street lights around the location of high voltage areas or into other forms. The design of this prototype works like an antenna in general that captures electromagnetic signals and converts them into AC waves. With a capacitor that can store the potential energy of AC and Schottky diode waves created specifically for low frequency waves, make the current into one direction (DC). From the research results obtained the current generated from the radiation is very small even though the voltage is big enough.Keywords : Radiance Energy, Joule Thief, and  LED Module.

scholarly journals Integral Equations for Problems on Wave Propagation in Near-Earth Plasma

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1395
Author(s):  
Danila Kostarev ◽  
Dmitri Klimushkin ◽  
Pavel Mager
Keyword(s):  
Magnetic Field ◽  
Integral Equations ◽  
Field Potential ◽  
Low Frequency ◽  
Fredholm Equation ◽  
Compression Waves ◽  
Parallel Component ◽  
Electric Field Potential ◽  
The Magnetic Field ◽  
Low Frequency Waves

We consider the solutions of two integrodifferential equations in this work. These equations describe the ultra-low frequency waves in the dipol-like model of the magnetosphere in the gyrokinetic framework. The first one is reduced to the homogeneous, second kind Fredholm equation. This equation describes the structure of the parallel component of the magnetic field of drift-compression waves along the Earth’s magnetic field. The second equation is reduced to the inhomogeneous, second kind Fredholm equation. This equation describes the field-aligned structure of the parallel electric field potential of Alfvén waves. Both integral equations are solved numerically.

The Effect of Magnetic Field on the Hydration of Nanoscopic Hydrophobic N-Alkane Plates

2011 ◽  
Vol 228-229 ◽  
pp. 1007-1011
Author(s):  
Wei Wei Zhang ◽  
Long Qiu Li ◽  
Guang Yu Zhang ◽  
Hui Juan Dong
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Dynamics Simulation ◽  
Free Energy Barrier ◽  
Confined Water ◽  
Magnetic Exposure ◽  
Hydrophobic Solutes ◽  
The Magnetic Field ◽  
Density Of Water ◽  
Induced Adsorption

The effect of an external magnetic field on the hydration behavior of nanoscopic n-octane plates has been extensively investigated using molecular dynamics simulation in an isothermal-isobaric ensemble. The solute plates with different intermolecular spacing have also been considered to examine the effect of the topology of hydrophobic plates on the adsorption behavior of confined water in the presence of an external magnetic field with an intensity ranging from 0.1T to 1 T. The results demonstrate that magnetic exposure decreases the density of water for the plates with intermolecular spacing of a0 = 4 and 5 Å. This suggests that the free energy barrier for evaporation can be lowered by the applied field, and the hydrophobic solutes consisting of condensed n-octane molecules are apt to aggregate in the aqueous solution. In contrast, the magnetic field improves the dissolution or wetting of solutes comprised of loosely packed n-octane plates of a0=7Å. A magnetic-field-induced adsorption-to-desorption translation, which is in agreement with the experimental results provided by Ozeki, has also been observed for the plates with intermolecular spacing of a0 = 6 Å.

scholarly journals Feasibility of Probing the Filler Restructuring in Magnetoactive Elastomers by Ultra-Small-Angle Neutron Scattering

2021 ◽  
Vol 11 (10) ◽  
pp. 4470
Author(s):  
Inna A. Belyaeva ◽  
Jürgen Klepp ◽  
Hartmut Lemmel ◽  
Mikhail Shamonin
Keyword(s):  
Magnetic Field ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Iron Particles ◽  
Filler Particles ◽  
The Magnetic Field ◽  
Magnetoactive Elastomer

Ultra-small-angle neutron scattering (USANS) experiments are reported on isotropic magnetoactive elastomer (MAE) samples with different concentrations of micrometer-sized iron particles in the presence of an in-plane magnetic field up to 350 mT. The effect of the magnetic field on the scattering curves is observed in the scattering vector range between 2.5 × 10−5 and 1.85 × 10−4 Å−1. It is found that the neutron scattering depends on the magnetization history (hysteresis). The relation of the observed changes to the magnetic-field-induced restructuring of the filler particles is discussed. The perspectives of employing USANS for investigations of the internal microstructure and its changes in magnetic field are considered.

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