FLAT CIRCULAR SOLENOID BETWEEN MASSIVE BIFILAR COILS. ANALYSIS OF ELECTROMAGNETIC PROCESSES

An analysis and numerical estimates of induction effects in the metal of a flat circular solenoid located between the branches of an external bifilar coil in a flat inductor system excited by unidirectional currents in the bifilar windings are presented. Such a device, the design of which was first proposed earlier by the authors of this work, is of practical interest for circuits of equipment for magnetic-pulse processing of metals. The use of the considered inductor system makes it possible to minimize the influence of induction effects on electromagnetic processes in the metal of the internal inductor. Numerical estimates are obtained for the induced currents excited in the metal of the inner circular inductor placed between the outer windings of the bifilar coil. It is shown that in the low-frequency mode of acting fields, the time dependence of the excited current is a derivative of the time dependence of the exciting current and the transverse distribution of the current in the metal of the internal inductor is a linear dependence passing through the central axis of the inductor. In the high-frequency regime of acting fields, the time dependence and the radial distribution of the excited current coincide with the corresponding analogs for the exciting current, and the transverse distribution of the induced current is characteristic of a sharp surface effect, when the induced current is displaced to the boundary surfaces of the metal. It is proved that the minimum influence of the fields of the external bifilar on the electromagnetic processes in the internal inductor should be observed in the low-frequency mode, when the spatial superposition of multidirectional induced currents adds up to the zero value of the excited electromotive force of induction. The results of the analysis based on the specific calculations performed are aimed at finding the conditions for the successful technical implementation of the proposed inductor system. The creation of workable models of the proposed inductor systems and experiments to determine the real conditions for their maximum efficiency are seen as very promising in the direction of subsequent research.

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ELECTROMAGNETIC PROCESSES IN A SYSTEM WITH A PLANE CIRCULAR SOLENOID BETWEEN MASSIVE BIFILARY COILS

Electromechanical and energy saving systems ◽

10.30929/2072-2052.2021.3.55.8-14 ◽

2021 ◽

Vol 3 (55) ◽

pp. 8-14

Author(s):

Yu. Batygin ◽

◽

T. Gavrilova ◽

Ev. Chaplygin ◽

S. Shinderuk ◽

...

Keyword(s):

Exact Solution ◽

Surface Effect ◽

Finite Thickness ◽

Low Frequency ◽

Frequency Mode ◽

Maximum Efficiency ◽

Magnetic Pulse ◽

Induced Current ◽

Transverse Distribution ◽

Electromagnetic Processes

Purpose. Currently, in order to save materials and energy costs, devices have been developed using inductor systems with bifilar coils used in equipment for magnetic-pulse processing of metals. The purpose of this work is to obtain design relations based on a rigorous solution of the edge electrodynamics for the analysis of electromagnetic processes in a real metal of a circular solenoid of finite thickness placed between massive multi-turn coils of a bifilar with unidirectional currents in a flat inductor system. Methodology. To solve this problem, Maxwell’s equations with appropriate boundary conditions and Laplace transforms were used. Results. Based on the exact solution of the boundary value problem, the space-time function of the density of the induced current, which arises in a flat solenoid when the system is excited by harmonic unidirectional currents in massive bifilar windings, is obtained. On the basis of numerical calculations, it was found that in the low-frequency mode, the transverse distribution of the induced current is linear, symmetric about the central axis of the inductor. In the high-frequency mode, the transverse distribution of the induced current is characteristic of the case of a sharp surface effect. The conditions for the minimum influence of the fields of the external bifilar on the processes in the internal inductor are revealed. Originality. The novelty of this work lies in proposing the idea of the design of the inductor system, as well as in the exact solution of the electrodynamics problem and obtaining the calculated expressions for the analysis of electromagnetic processes. Practical value. On the basis of the obtained formulas and the performed calculations, the efficiency of the proposed calculation model has been proved, which makes it possible to use it as a basic model for similar inductor systems in determining the real conditions of their maximum efficiency. Figures 2, references 17.

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An experimental study of very-low-frequency mode coupling and polarization reversal

Journal of Geophysical Research Atmospheres ◽

10.1029/ja076i004p00960 ◽

1971 ◽

Vol 76 (4) ◽

pp. 960-971 ◽

Cited By ~ 19

Author(s):

Paul Rodriguez ◽

Donald A. Gurnett

Keyword(s):

Experimental Study ◽

Mode Coupling ◽

Low Frequency ◽

Frequency Mode ◽

Polarization Reversal ◽

Very Low Frequency ◽

Low Frequency Mode

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Observations of a low-frequency mode in a linear multiple mirror

The Physics of Fluids ◽

10.1063/1.865416 ◽

1985 ◽

Vol 28 (7) ◽

pp. 2302

Author(s):

M. A. Makowski ◽

G. A. Emmert

Keyword(s):

Low Frequency ◽

Frequency Mode ◽

Low Frequency Mode

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Light Scattering from Pulsed Laser Deposited BaBi4Ti4O15 Thin Films

MRS Proceedings ◽

10.1557/proc-623-167 ◽

2000 ◽

Vol 623 ◽

Author(s):

R.K. Soni ◽

Anju Dixit ◽

R. S. Katiyar ◽

A. Pignolet ◽

K.M. Satyalakshmi ◽

...

Keyword(s):

Thin Films ◽

Light Scattering ◽

Room Temperature ◽

Layer Structure ◽

Low Frequency ◽

Pulsed Laser ◽

Buffer Layers ◽

Frequency Mode ◽

High Frequency Vibrations ◽

Low Frequency Mode

AbstractLight scattering investigations are carried out on BaBi4Ti4O15 (BBiT) which is a member of the Bi-layer structure ferroelectric oxide with n = 4. The BBiT thin films, thickness ∼ 300 nm, were grown on epitaxial conducting LaNiO3 electrodes on epitaxial buffer layers on (100) silicon by pulsed laser deposition. Micro-Raman measurements performed on these films reveal a sharp low-frequency mode at 51 cm−1 along with broad highfrequeficy modes corresponding to other lattice vibrations including TiO6 octahedra. No temperature dependence of the low frequency mode is seen while a weak dependence of the broad high frequency vibrations are observed in the mixed oriented regions. Raman polarization carried out at room temperature indicates that the prominent modes have Alg and Eg symmetries in the BaBi4Ti4O15 thin films.

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Local sensitivity of an electrochemical quartz crystal microbalance: Spatial localization of the low frequency mode

Review of Scientific Instruments ◽

10.1063/1.1145993 ◽

1995 ◽

Vol 66 (2) ◽

pp. 1136-1141 ◽

Cited By ~ 8

Author(s):

R. Oltra ◽

I. O. Efimov

Keyword(s):

Quartz Crystal Microbalance ◽

Quartz Crystal ◽

Low Frequency ◽

Spatial Localization ◽

Electrochemical Quartz Crystal Microbalance ◽

Frequency Mode ◽

Local Sensitivity ◽

Low Frequency Mode

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Interactions between second mode and low-frequency waves in a hypersonic boundary layer

Journal of Fluid Mechanics ◽

10.1017/jfm.2017.233 ◽

2017 ◽

Vol 820 ◽

pp. 693-735 ◽

Cited By ~ 65

Author(s):

Xi Chen ◽

Yiding Zhu ◽

Cunbiao Lee

Keyword(s):

Boundary Layer ◽

Parametric Resonance ◽

Low Frequency ◽

Frequency Mode ◽

Linear Stability Theory ◽

Hypersonic Boundary Layer ◽

Reynolds Stresses ◽

Second Mode ◽

Low Frequency Mode ◽

Low Frequency Waves

The stability of a hypersonic boundary layer on a flared cone was analysed for the same flow conditions as in earlier experiments (Zhang et al., Acta Mech. Sinica, vol. 29, 2013, pp. 48–53; Zhu et al., AIAA J., vol. 54, 2016, pp. 3039–3049). Three instabilities in the flared region, i.e. the first mode, the second mode and the Görtler mode, were identified using linear stability theory (LST). The nonlinear-parabolized stability equations (NPSE) were used in an extensive parametric study of the interactions between the second mode and the single low-frequency mode (the Görtler mode or the first mode). The analysis shows that waves with frequencies below 30 kHz are heavily amplified. These low-frequency disturbances evolve linearly at first and then abruptly transition to parametric resonance. The parametric resonance, which is well described by Floquet theory, can be either a combination resonance (for non-zero frequencies) or a fundamental resonance (for steady waves) of the secondary instability. Moreover, the resonance depends only on the saturated state of the second mode and is insensitive to the initial low-frequency mode profiles and the streamwise curvature, so this resonance is probably observable in boundary layers over straight cones. Analysis of the kinetic energy transfer further shows that the rapid growth of the low-frequency mode is due to the action of the Reynolds stresses. The same mechanism also describes the interactions between a second-mode wave and a pair of low-frequency waves. The only difference is that the fundamental and combination resonances can coexist. Qualitative agreement with the experimental results is achieved.

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