Low-frequency waves in inhomogeneous magnetic fields

1979 ◽  
Vol 21 (2) ◽  
pp. 279-286 ◽  
Author(s):  
A. Hruška
Keyword(s):  
Low Frequency ◽  
Sound Waves ◽  
Isotropic Plasma ◽  
Phase Velocities ◽  
Magnetic Field Topology ◽  
Hot Plasma ◽  
Propagation Of Waves ◽  
The Magnetic Field ◽  
Low Frequency Waves ◽  
Scale Length

Propagation of waves in inhomogeneous, hot, isotropic plasma is described, assuming that the wavelength is much smaller than the scale-length of the plasma. The effect of the magnetic field topology on properties of waves is discussed in some detail. Coupling between the modes of oscillations is always present in an inhomogeneous ‘hot’ plasma. It is particularly strong for magneto- dynamic and sound waves propagating essentially along the fleidlines in the vicinity of a point where the phase velocities of the two modes are equal.

scholarly journals Alfvén waves in the foreshock propagating upstream in the plasma rest frame: statistics from Cluster observations

2004 ◽  
Vol 22 (7) ◽  
pp. 2315-2323 ◽  
Author(s):  
Y. Narita ◽  
K.-H. Glassmeier ◽  
S. Schäfer ◽  
U. Motschmann ◽  
M. Fränz ◽  
...  
Keyword(s):  
Rest Frame ◽  
Low Frequency ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Phase Velocities ◽  
Wave Numbers ◽  
The Magnetic Field ◽  
Proton Cyclotron ◽  
Low Frequency Waves ◽  
Alfven Velocity

Abstract. We statistically study various properties of low-frequency waves such as frequencies, wave numbers, phase velocities, and polarization in the plasma rest frame in the terrestrial foreshock. Using Cluster observations the wave telescope or k-filtering is applied to investigate wave numbers and rest frame frequencies. We find that most of the foreshock waves propagate upstream along the magnetic field at phase velocity close to the Alfvén velocity. We identify that frequencies are around 0.1xΩcp and wave numbers are around 0.1xΩcp/VA, where Ωcp is the proton cyclotron frequency and VA is the Alfvén velocity. Our results confirm the conclusions drawn from ISEE observations and strongly support the existence of Alfvén waves in the foreshock.

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.

scholarly journals Propagation of high frequency waves in the quiet solar atmosphere

2008 ◽  
pp. 87-99 ◽  
Author(s):  
A. Andic
Keyword(s):  
Solar Atmosphere ◽  
High Frequency ◽  
Low Frequency ◽  
Magnetic Structures ◽  
Partial Heating ◽  
Fabry Perot ◽  
High Frequency Waves ◽  
Propagation Of Waves ◽  
The Waves ◽  
Low Frequency Waves

High-frequency waves (5 mHz to 20 mHz) have previously been suggested as a source of energy accounting for partial heating of the quiet solar atmosphere. The dynamics of previously detected high-frequency waves is analyzed here. Image sequences were taken by using the German Vacuum Tower Telescope (VTT), Observatorio del Teide, Izana, Tenerife, with a Fabry-Perot spectrometer. The data were speckle reduced and analyzed with wavelets. Wavelet phase-difference analysis was performed to determine whether the waves propagate. We observed the propagation of waves in the frequency range 10 mHz to 13 mHz. We also observed propagation of low-frequency waves in the ranges where they are thought to be evanescent in the regions where magnetic structures are present.

scholarly journals Four-wave Processes Involving Two Low Frequency Waves

1986 ◽  
Vol 39 (6) ◽  
pp. 891 ◽  
Author(s):  
DB Melrose
Keyword(s):  
Transverse Wave ◽  
Major Part ◽  
Nonlinear Response ◽  
Interplanetary Medium ◽  
Wave Process ◽  
Low Frequency ◽  
Langmuir Wave ◽  
Sound Waves ◽  
Wave Processes ◽  
Low Frequency Waves

The probability is calculated for a four-wave process in which a Langmuir wave combines with two low frequency (ion sound) waves to produce another Langmuir wave or a transverse wave. The major part of the calculation involves relevant approximations to the quadratic and cubic nonlinear response tensors. An estimate based on observational data from the interplanetary medium suggests that the four-wave process may be significant in solar radiophysics.

Induced Three-wave Interactions in Eclipsing Pulsars

1995 ◽  
Vol 12 (1) ◽  
pp. 71-75
Author(s):  
Qinghuan Luo ◽  
D. B. Melrose
Keyword(s):  
Thermal Effects ◽  
Cold Plasma ◽  
Low Frequency ◽  
Wave Interaction ◽  
Wave Interactions ◽  
Frequency Wave ◽  
Frequency Branch ◽  
High Frequency Waves ◽  
The Magnetic Field ◽  
Low Frequency Waves

AbstractThree-wave interactions involving two high-frequency waves (in the same mode) and a low-frequency wave are discussed and applied to pulsar eclipses. When the magnetic field is taken into account, the low-frequency waves can be the ω-mode (the low-frequency branch of the ordinary mode) or the z-mode (the low-frequency branch of the extraordinary mode). It is shown that in the cold plasma approximation, effective growth of the low-frequency waves due to an anisotropic photon beam can occur only for z-mode waves near the resonance frequency. In the application to pulsar eclipses, the cold plasma approximation may not be adequate and we suggest that when thermal effects are included, three-wave interaction involving low-frequency cyclotron waves (e.g. Bernstein modes) is a plausible candidate for pulsar eclipses

scholarly journals PEMANFAATAN RADIASI ENERGI TEGANGAN 150 KV UNTUK LAMPU LED PENERANGAN JALAN

Kilat ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 51-55
Author(s):  
Redaksi Tim Jurnal
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.

scholarly journals Statistical phase propagation and dispersion analysis of low frequency waves in the magnetosheath

2005 ◽  
Vol 23 (10) ◽  
pp. 3339-3349 ◽  
Author(s):  
S. Schäfer ◽  
K.-H. Glassmeier ◽  
Y. Narita ◽  
K. H. Fornaçon ◽  
I. Dandouras ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Plasma Flow ◽  
Low Frequency ◽  
Dispersion Analysis ◽  
Statistical Dispersion ◽  
Mirror Mode ◽  
Analysis Of Dispersion ◽  
The Magnetic Field ◽  
Wave Properties ◽  
Low Frequency Waves

Abstract. We present the results of a statistical analysis of low-frequency fluctuations in the high latitude regions of the dayside magnetosheath using CLUSTER as a wave telescope. Magnetic field observations are used to determine wave propagation directions and wave numbers for selected frequencies. Using observations of the plasma flow velocity we correct for the Doppler shift, in order to calculate frequencies and phase velocities in the plasma rest frame. This provides us with the possibility to perform a statistical dispersion analysis and to investigate various wave properties, such as the phase velocity and the propagation angle between k and B. The analysis of dispersion distributions and Friedrichs diagrams results in the identification of different wave populations. We find a multiplicity of standing structures (mirror modes) convected with the plasma flow and a large number of Alfvénic waves. The results confirm previous magnetosheath wave studies, such as ISSE or AMPTE spacecraft observations, but we also find a small number of mirror mode-like waves that have propagation speeds up to the local Alfvén velocity, quasi-perpendicular to the magnetic field.

scholarly journals Alfvén waves in the near-PSBL lobe: Cluster observations

2006 ◽  
Vol 24 (3) ◽  
pp. 1001-1013 ◽  
Author(s):  
T. Takada ◽  
R. Nakamura ◽  
W. Baumjohann ◽  
K. Seki ◽  
Z. Vörös ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Ion Beam ◽  
Low Frequency ◽  
Poynting Flux ◽  
Field Fluctuations ◽  
The Rich ◽  
Field Lines ◽  
The Waves ◽  
The Magnetic Field ◽  
Low Frequency Waves

Abstract. Electromagnetic low-frequency waves in the magnetotail lobe close to the PSBL (Plasma Sheet Boundary Layer) are studied using the Cluster spacecraft. The lobe waves show Alfvénic properties and transport their wave energy (Poynting flux) on average toward the Earth along magnetic field lines. Most of the wave events are rich with oxygen (O+) ion plasma. The rich O+ plasma can serve to enhance the magnetic field fluctuations, resulting in a greater likelihood of observation, but it does not appear to be necessary for the generation of the waves. Taking into account the fact that all events are associated with auroral electrojet enhancements, the source of the lobe waves might be a substorm-associated instability, i.e. some instability near the reconnection site, or an ion beam-related instability in the PSBL.

scholarly journals The BepiColombo–Mio Magnetometer en Route to Mercury

2020 ◽  
Vol 216 (8) ◽  
Author(s):  
W. Baumjohann ◽  
A. Matsuoka ◽  
Y. Narita ◽  
W. Magnes ◽  
D. Heyner ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Power Supply ◽  
Low Frequency ◽  
Internal Field ◽  
High Time Resolution ◽  
Fluxgate Magnetometer ◽  
Near Surface ◽  
The Magnetic Field ◽  
Low Frequency Waves ◽  
Inner Heliosphere

AbstractThe fluxgate magnetometer MGF on board the Mio spacecraft of the BepiColombo mission is introduced with its science targets, instrument design, calibration report, and scientific expectations. The MGF instrument consists of two tri-axial fluxgate magnetometers. Both sensors are mounted on a 4.8-m long mast to measure the magnetic field around Mercury at distances from near surface (initial peri-center altitude is 590 km) to 6 planetary radii (11640 km). The two sensors of MGF are operated in a fully redundant way, each with its own electronics, data processing and power supply units. The MGF instrument samples the magnetic field at a rate of up to 128 Hz to reveal rapidly-evolving magnetospheric dynamics, among them magnetic reconnection causing substorm-like disturbances, field-aligned currents, and ultra-low-frequency waves. The high time resolution of MGF is also helpful to study solar wind processes (through measurements of the interplanetary magnetic field) in the inner heliosphere. The MGF instrument firmly corroborates measurements of its companion, the MPO magnetometer, by performing multi-point observations to determine the planetary internal field at higher multi-pole orders and to separate temporal fluctuations from spatial variations.

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