scholarly journals The initial stage of the plasma formation at skin explosion of cylindrical conductors

2021 ◽  
Vol 2064 (1) ◽  
pp. 012012
Author(s):  
I M Datsko ◽  
N A Labetskaya ◽  
S A Chaikovsky ◽  
V A Van’kevich ◽  
V I Oreshkin
Keyword(s):  
Magnetic Field ◽  
Magnetic Induction ◽  
Dense Plasma ◽  
Electrical Explosion ◽  
Plasma Formation ◽  
Initial Stage ◽  
Different Diameters ◽  
Cylindrical Conductors ◽  
The Magnetic Field ◽  
Uniform Plasma

Abstract The formation of plasma on the surface of the electrically exploded conductor is a key issue in terms of the energy introduced into the metal substance. The purpose of this work was to study the dynamics of dense plasma formation on the metal surface at magnetic induction values of 200-600 T and its rising rates of (2-6) T/ns. The experiments were carried out on a terawatt MIG generator with current amplitude up to 2.5 MA and rise time of 100 ns. In experiments, skin electrical explosion of cylindrical conductors made of different materials and with different diameters was studied. The formation of plasma on the surface of the conductor was recorded using a four-frame optical camera with an exposure time of 3 ns for each frame. It was shown that when the current increases, “spots” appear on the surface of a cylindrical conductor. These spots are the centers of plasma formation. Later in the time, longitudional plasma channels were registered. In course of subsequent merging of the channels relatively uniform plasma formation occurs. The paper discusses the features of the dynamics of plasma formation as a function of the peak and the rising rate of the magnetic field induction.

Nonlinear evolution of a wave packet propagating along a hot magnetoplasma column

1987 ◽  
Vol 37 (1) ◽  
pp. 107-115
Author(s):  
B. Ghosh ◽  
K. P. Das
Keyword(s):  
Magnetic Field ◽  
Multiple Scales ◽  
Nonlinear Evolution ◽  
Axial Magnetic Field ◽  
Modulational Instability ◽  
Wave Train ◽  
Dielectric Medium ◽  
Ion Effects ◽  
The Magnetic Field ◽  
Uniform Plasma

The method of multiple scales is used to derive a nonlinear Schrödinger equation, which describes the nonlinear evolution of electron plasma ‘slow waves’ propagating along a hot cylindrical plasma column, surrounded by a dielectric medium and immersed in an essentially infinite axial magnetic field. The temperature is included as well as mobile ion effects for ail possible modes of propagation along the magnetic field. From this equation the condition for modulational instability for a uniform plasma wave train is determined.

The interface of a uniform plasma enveloped by the magnetic field of a system of line currents

1969 ◽  
Vol 3 (4) ◽  
pp. 651-660 ◽  
Author(s):  
C. Sozou
Keyword(s):  
Magnetic Field ◽  
Inverse Problem ◽  
Complex Variable ◽  
Field Boundary ◽  
Equilibrium Configurations ◽  
Minimum Number ◽  
The Magnetic Field ◽  
Uniform Plasma

It is shown that complex variable transformations, suitable for obtaining the solution for the field boundary of a system of line currents confined in one cavity by a perfectly conducting uniform plasma, can be used for obtaining the solution to the inverse problem where a perfectly conducting uniform plasma is confined in one cavity by a system of line currents. It is deduced that the minimum number of line currents for confining (not stably) a plasma is two. The equilibrium configurations for several special but simple cases are investigated and discussed.

Fast magnetic field penetration into low resistivity plasma

2017 ◽  
Vol 83 (1) ◽  
Author(s):  
Amnon Fruchtman
Keyword(s):  
Magnetic Field ◽  
Energy Dissipation ◽  
Electric Field ◽  
Density Gradient ◽  
Magnetic Energy ◽  
Measured Velocity ◽  
Magnetic Field Penetration ◽  
The Magnetic Field ◽  
Uniform Plasma ◽  
Field Penetration

Penetration of a magnetic field into plasma that is faster than resistive diffusion can be induced by the Hall electric field in a non-uniform plasma. This mechanism explained successfully the measured velocity of the magnetic field penetration into pulsed plasmas. Major related issues have not yet been resolved. Such is the theoretically predicted, but so far not verified experimentally, high magnetic energy dissipation, as well as the correlation between the directions of the density gradient and of the field penetration.

Magnetic Induction Effect of Amorphous Ribbon Modified by Rare-Earth

2010 ◽  
Vol 152-153 ◽  
pp. 587-591 ◽  
Author(s):  
Da Guo Jiang
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
Amorphous Alloy ◽  
Magnetic Induction ◽  
Amorphous Ribbon ◽  
Induction Effect ◽  
Temperature Influence ◽  
Rare Earth La ◽  
The Magnetic Field ◽  
Rare Earth Content

Prepared rare-earth La modified amorphous ribbon by doping Rare-earth La in Fe78Si9B13 amorphous alloy. Investigated rare-earth content and temperature, as well as their influence on the magnetic induction effect and it’s amplitude. The results show that, when magnetic field is less than 1356 A / m, with the increase of Rare-earth content ,the magnetic induction effect first increased and then decreased, when the magnetic field strength greater than 1356 A / m, the Rare-earth content influence little on magnetic induction effect , changing amplitude of magnetic induction effect shows first increased and then decreased with increasing Rare-earth content; temperature influence little on the magnitude of magnetic induction effect.

Influence of Annealing Process on the Magnetic Induction Effect of FeSiB Amorphous Alloy Ribbons

2010 ◽  
Vol 428-429 ◽  
pp. 470-474
Author(s):  
Xiao Jun Wang ◽  
Xiao Guang Fu
Keyword(s):  
Magnetic Field ◽  
Amorphous Alloy ◽  
Magnetic Induction ◽  
Annealing Process ◽  
Induction Effect ◽  
Positive Pulse ◽  
Field Density ◽  
Frequency Magnetic Field ◽  
Input Waveform ◽  
The Magnetic Field

The influences of frequency, magnetic field density, importing waveform and annealing process on the rangeability of Fe78Si9B13 amorphous alloy ribbon’s magnetic induction effect were studied. The results showed that the rangeability increased with the magnetic field density increased when frequency below 75 kHz, but decreased with the field density increased when frequency over 75 kHz. Compared with quenched ribbons, the rangeability increase after annealed, and the rangeability reached maximum annealed at 300°C for 1.5 hours. When the input waveform is 75 kHz positive pulse and field intensity is 358A/m, the rangeability the quenched ribbons was 2.27V but it reached to 2.85V after annealed at 300°C for 1.5hours.

scholarly journals Formation of an elongated plasma column by a magnetic confinement of a laser-produced plasma

1992 ◽  
Vol 10 (4) ◽  
pp. 767-776 ◽  
Author(s):  
T. Pisarczyk ◽  
A. Faryński ◽  
H. Fiedorowicz ◽  
P. Gogolewski ◽  
M. Kuśnierz ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Laser Plasma ◽  
Plasma Column ◽  
Target Region ◽  
X Ray ◽  
Laser Probing ◽  
Single Turn ◽  
Magnetic Coils ◽  
The Magnetic Field ◽  
Uniform Plasma

In this article, we present the formation of an elongated plasma column by combining a laser plasma with an external magnetic field. The laser plasma is produced by irradiating solid targets with a focused Nd-glass laser. The targets were placed on the axis of the two, single-turn magnetic coils, which provided a magnetic field up to 500 kg in the target region. The expanding laser plasma is confined by the magnetic field and an elongated and uniform plasma column is formed on the axis of the coils. The plasma column emits strong, soft X-ray radiation. The pinhole photographs show that the plasma column is at least 5 mm long. To study the interaction of the expanding laser plasma with a magnetic field, the laser probing diagnostic was used.

Simulation Research on the Magnetic Field of the Positioning Permanent Magnet for MEMS inside Human Body Based on Ansoft

2014 ◽  
Vol 596 ◽  
pp. 67-71
Author(s):  
Xiu Quan Liu ◽  
Yan Hong Li
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Magnetic Dipole ◽  
Human Body ◽  
Magnetic Induction ◽  
Dipole Model ◽  
Magnetization Direction ◽  
Simulation Research ◽  
Magnetic Induction Intensity ◽  
The Magnetic Field

the magnetic dipole model of the cylindrical permanent magnet was introduced. Then, based on Ansoft software, the simulation model of the cylindrical permanent magnet was established, and the influence of some parameters, such as the height, radius and magnetization direction on the magnetic induction intensity ,were studied; at the same time, under these two models the calculation was compared, the result shows the the magnetic dipole model is applied on condition that distance is nine times greater than the cylindrical permanent magnet size.

scholarly journals Influence of magnetic field on change of activation energy during pre-sowing seed treatment

2020 ◽  
pp. 17-25
Author(s):  
V. Savchenko ◽  
◽  
O. Synyavsky ◽  
D. Rosengart ◽  
V. Bunko ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Activation Energy ◽  
Magnetic Induction ◽  
Seed Treatment ◽  
Crop Yields ◽  
Magnetic Field Gradient ◽  
Agricultural Crops ◽  
Experimental Planning ◽  
Sowing Seed ◽  
The Magnetic Field

It is possible to increase crop yields and product quality through the use of electrophysical methods of pre-sowing seed treatment, among which pre-sowing seed treatment in a magnetic field is promising. For successful introduction of magnetic seed treatment in production it is necessary to establish mode parameters of treatment and their optimum values. To do this, it is necessary to establish the effect of the magnetic field on the change in activation energy during pre-sowing seed treatment. The aim of the study was to determine the change in activation energy during pre-sowing treatment of crop seeds in a magnetic field. To determine the change in the activation energy, the change in the biopotential of the seed during its treatment in a magnetic field was experimentally investigated by the experimental planning method. It was found that the change in seed biopotential depends on the square of the magnetic induction and the velocity of the seed in a magnetic field. An analytical expression was obtained that relates the change in activation energy to the change in seed biopotential, which made it possible to establish the dependence of the change in activation energy on the treatment parameters. It was found that the greatest seed biopotential and activation energy change at a magnetic induction of 0.065 T, a magnetic field gradient of 0.57 T/m and a velocity of 0.4 m/s. Under this mode of pre-sowing seed treatment of agricultural crops, the activation energy changes by 3.1 - 5.7 kJ/g-eq.

scholarly journals Determination Transition Resistance of Cathode-Polarized Main Pipeline on Magnetometery Data

2021 ◽  
Vol 6 (6) ◽  
pp. 1729-1740
Author(s):  
Vladimir N. Krizsky ◽  
Pavel N. Alexandrov ◽  
Alexey A. Kovalskii ◽  
Sergey V. Victorov
Keyword(s):  
Magnetic Field ◽  
Inverse Problem ◽  
Cathodic Protection ◽  
Magnetic Induction ◽  
Solution Method ◽  
Main Pipeline ◽  
Induction Vector ◽  
Magnetic Induction Vector ◽  
Transition Resistance ◽  
The Magnetic Field

The article deals with the inverse problem of determining the transient resistance of the main pipeline insulating coating. For this, UAV measurements of the magnetic induction vector modulus of the magnetic field excited by the system of electrochemical cathodic protection of pipelines are used. The solution method is based on Tikhonov's method for finding the extremal of the regularizing functional. The developed algorithm is implemented in software. The results of computational experiments are presented.

Electromagnetic Nondestructive Testing Model and Surface Magnetic Field Analysis for Circumferential Cracks on Metal Rod

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Feng Jiang ◽  
Shulin Liu ◽  
Shaojie Xin ◽  
Hongli Zhang
Keyword(s):  
Magnetic Field ◽  
Analytical Model ◽  
Magnetic Induction ◽  
Crack Depth ◽  
Field Analysis ◽  
Surface Magnetic Field ◽  
Circumferential Crack ◽  
Inner Surface ◽  
Magnetic Induction Intensity ◽  
The Magnetic Field

Abstract In this paper, an analytical model for a metal rod with a coating layer is proposed to evaluate circumferential crack from the signals of the surface magnetic field. In the proposed model, magnetic vector equations for four regions of space were built, and series expressions of the magnetic field were proposed by the truncated region eigenfunction method. The calculation results can show the three-dimensional distribution of axial and radial magnetic induction intensities on the surface of a metal rod clearly. In addition, the analytical model is verified by using comsol finite element simulation, which also demonstrates that induced eddy currents on the inner surface of the metal rod with cracks appear to be propelled toward the inner layer of the metal rod and the presence of a circumferential crack directly causes a decrease in the induced eddy current on the inner surface of the rod. The results calculated from the analytical model indicated that the model is capable of providing an accurate variation in the magnetic field due to circumferential cracks at different depths. The analytical results showed that the radial magnetic induction intensity increases by 0.16 × 10−3 T, while the axial magnetic induction intensity decreases by 0.3 × 10−3 T as the crack depth increases from 0 to 3 mm.

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