ON THE APPLICATION OF PLASMA KINETIC THEORY TO IONIC SOUND-WAVE EXPERIMENTS IN MAGNETIC FIELDS

1965 ◽  
Vol 43 (10) ◽  
pp. 1750-1765 ◽  
Author(s):  
M. J. Haggerty
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Critical Frequency ◽  
Magnetic Field Intensity ◽  
Sound Waves ◽  
Cyclotron Radius ◽  
The Mean ◽  
The Magnetic Field ◽  
Theoretical Results

The kinetic theoretical results for a homogeneous plasma in a uniform magnetic field are discussed qualitatively. The role of the mean cyclotron radius as a natural long-range cutoff is clarified. A relationship between a critical frequency for ionic sound waves and the magnetic-field intensity is predicted.

scholarly journals Nonlinear Dynamo in a Disk Galaxy

1993 ◽  
Vol 157 ◽  
pp. 349-353
Author(s):  
A. Poezd ◽  
A. Shukurov ◽  
D.D. Sokoloff
Keyword(s):  
Magnetic Field ◽  
Milky Way ◽  
Dynamo Model ◽  
The Galaxy ◽  
Seed Field ◽  
Andromeda Nebula ◽  
The Mean ◽  
Dynamo Equation ◽  
The Magnetic Field

A nonlinear thin-disk galactic dynamo model based on α-quenching is proposed. Assuming that the mean helicity depends on the magnetic field strength averaged across the disk, we derive a universal form of nonlinearity in the radial dynamo equation. We discuss the evolution of the regular magnetic field in the Milky Way and the Andromeda Nebula. It is argued that the reversals of the regular magnetic field in the Galaxy are a relic inherited from the structure of the seed field. We also briefly discuss the role of the turbulent diamagnetism and the effects of galactic evolution on the dynamo.

The role of the magnetic field intensity and geometry in the type III burst generation

Solar Physics ◽  
1990 ◽  
Vol 130 (1-2) ◽  
pp. 31-37 ◽  
Author(s):  
P. Zlobec ◽  
V. Ruždjak ◽  
B. Vršnak ◽  
M. Karlický ◽  
M. Messerotti
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Type Iii ◽  
The Magnetic Field

Characteristics of Ultrasound Propagation in a Magnetic Fluid Under Uniform Magnetic Field

2003 ◽  
Author(s):  
Masaaki Motozawa ◽  
Tatsuo Sawada
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fluid ◽  
Uniform Magnetic Field ◽  
Colloidal Particles ◽  
Magnetic Field Intensity ◽  
Magnetic Field Direction ◽  
Ultrasound Propagation ◽  
Ultrasonic Propagation ◽  
The Magnetic Field

When an external magnetic field is applied to a magnetic fluid, some of the colloidal particles coagulate and form chain-like clusters. Properties of ultrasonic propagation wave are changed by these chain-like clusters. We carried out measurement of the ultrasonic propagation velocity in a magnetic fluid. Measurement were made by changing the magnetic field intensity from 0 mT to 570 mT, and the angle between the magnetic field direction and direction of the ultrasound propagation from 0° to 180°. The ultrasound frequencies were 1 MHz, 2 MHz and 4 MHz. Some of experimental results for the characteristics of ultrasound propagation in a magnetic fluid under a uniform magnetic field were reported.

scholarly journals The Role of Magnetic Fields in the Origin and Structure of Planetary Nebulae

1968 ◽  
Vol 34 ◽  
pp. 279-281
Author(s):  
Donald H. Menzel
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Planetary Nebulae ◽  
Ionized Gas ◽  
Symmetrical Structure ◽  
Image Position ◽  
The Magnetic Field

That the characteristic, quasi-symmetrical structure of planetary nebulae may result from the presence of imbedded magnetic fields has undoubtedly occurred to many astronomers. Gurzadian (1962), for example, employed the widely used equation where p is the pressure of the ionized gas and H the magnetic-field intensity. This equation specifies that the sum of the gas and magnetic pressures should be constant for a given value of the radius.

scholarly journals Ferrofluid flow due to a rotating disk in the presence of a non-uniform magnetic field

2016 ◽  
Vol 21 (2) ◽  
pp. 273-283 ◽  
Author(s):  
A. Bhandari ◽  
V. Kumar
Keyword(s):  
Mathematical Modeling ◽  
Magnetic Field ◽  
Field Intensity ◽  
Axial Velocity ◽  
Uniform Magnetic Field ◽  
Magnetic Field Intensity ◽  
Rotating Disk ◽  
Axial Direction ◽  
Magnetization Force ◽  
The Magnetic Field

AbstractThe flow of a ferrofluid due to a rotating disk in the presence of a non-uniform magnetic field in the axial direction is studied through mathematical modeling of the problem. Contour and surface plots in the presence of10kilo-ampere/meter,100kilo-ampere/meter magnetization force are presented here for radial, tangential and axial velocity profiles, and results are also drawn for the magnetic field intensity. These results are compared with the ordinary case where magnetization force is absent.

Revised reluctance model of the axial magnetic field intensity within giant magnetostrictive rod

2016 ◽  
Vol 231 (14) ◽  
pp. 2718-2729 ◽  
Author(s):  
Xue Guangming ◽  
Zhang Peilin ◽  
He Zhongbo ◽  
Li Xin ◽  
Zeng Wei ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Uniform Distribution ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Magnetic Circuit ◽  
Axial Magnetic Field ◽  
Integral Form ◽  
Giant Magnetostrictive Material ◽  
The Mean ◽  
The Magnetic Field

A theoretical magnetic field intensity model within giant magnetostrictive material was presented. This model was established just like the reluctance model, while could describe the non-uniform distribution flexibly for its integral form. This model employed magnetic circuit theorem calculating the mean of the magnetic field, while used a normalized function describing the distributing character. The distributing function was determined by Biot–Savart law and relative permeability of the material. The model was validated with the help of the experimental device. At last, the fitting degree of the model with the tested results in predicting the performance of the actuator is researched.

scholarly journals Double power-law spectra of energetic electrons in the Earth magnetotail

2013 ◽  
Vol 31 (1) ◽  
pp. 91-106 ◽  
Author(s):  
A. V. Artemyev ◽  
M. Hoshino ◽  
V. N. Lutsenko ◽  
A. A. Petrukovich ◽  
S. Imada ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Power Law ◽  
Relativistic Effects ◽  
Electron Acceleration ◽  
Relativistic Electrons ◽  
The Earth ◽  
Field Fluctuations ◽  
The Magnetic Field ◽  
Theoretical Results

Abstract. In this paper, we consider electron acceleration in the vicinity of X-line and corresponding formation of energy spectra. We develop an analytical model including the effect of the electron trapping by electrostatic fields and surfing acceleration. Speiser, Fermi and betatron mechanisms of acceleration are also taken into account. Analytical estimates are verified by the numerical integration of electron trajectories. The surfing mechanism and adiabatic heating are responsible for the formation of the double power-law spectrum in agreement with the previous studies. The energy of the spectrum knee is about ~150 keV for typical conditions of the Earth magnetotail. We compare theoretical results with the spacecraft observations of electron double power-law spectra in the magnetotail and demonstrate that the theory is able to describe typical energy of the spectra knee. We also estimate the role of relativistic effects and magnetic field fluctuations on the electron acceleration: the acceleration is more stable for relativistic electrons, while fluctuations of the magnetic field cannot significantly decrease the gained energy for typical magnetospheric conditions.

scholarly journals What Density of Magnetosheath Sodium Ions Can Provide the Observed Decrease in the Magnetic Field of the “Double Magnetopause” during the First MESSENGER Flyby?

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1168
Author(s):  
Elena Belenkaya ◽  
Ivan Pensionerov
Keyword(s):  
Magnetic Field ◽  
Analytical Approach ◽  
Field Structure ◽  
Sodium Ions ◽  
Plasma Parameters ◽  
Calculation Results ◽  
Magnetizing Current ◽  
The Magnetic Field ◽  
Density Excess

On 14 January 2008, the MESSENGER spacecraft, during its first flyby around Mercury, recorded the magnetic field structure, which was later called the “double magnetopause”. The role of sodium ions penetrating into the Hermean magnetosphere from the magnetosheath in generation of this structure has been discussed since then. The violation of the symmetry of the plasma parameters at the magnetopause is the cause of the magnetizing current generation. Here, we consider whether the change in the density of sodium ions on both sides of the Hermean magnetopause could be the cause of a wide diamagnetic current in the magnetosphere at its dawn-side boundary observed during the first MESSENGER flyby. In the present paper, we propose an analytical approach that made it possible to determine the magnetosheath Na+ density excess providing the best agreement between the calculation results and the observed magnetic field in the double magnetopause.

Connecting a Star’s Convection Zone with its Corona

1995 ◽  
Vol 12 (2) ◽  
pp. 180-185 ◽  
Author(s):  
D. J. Galloway ◽  
C. A. Jones
Keyword(s):  
Magnetic Field ◽  
Convection Zone ◽  
Flux Rope ◽  
Field System ◽  
Stellar Convection ◽  
Coronal Activity ◽  
Flux Concentration ◽  
Global Understanding ◽  
The Magnetic Field

AbstractThis paper discusses problems which have as their uniting theme the need to understand the coupling between a stellar convection zone and a magnetically dominated corona above it. Interest is concentrated on how the convection drives the atmosphere above, loading it with the currents that give rise to flares and other forms of coronal activity. The role of boundary conditions appears to be crucial, suggesting that a global understanding of the magnetic field system is necessary to explain what is observed in the corona. Calculations are presented which suggest that currents flowing up a flux rope return not in the immediate vicinity of the rope but rather in an alternative flux concentration located some distance away.

ORIENTATION DYNAMICS OF MAGNETORHEOLOGICAL FLUIDS SUBJECT TO ROTATING EXTERNAL FIELDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 758-766 ◽  
Author(s):  
SONIA MELLE ◽  
MIGUEL A. RUBIO ◽  
GERALD G. FULLER
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Simple Model ◽  
Critical Frequency ◽  
Optical Methods ◽  
Phase Lag ◽  
Rotating Magnetic Fields ◽  
Mr Fluids ◽  
Small Angle Light Scattering ◽  
The Magnetic Field

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.

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