Inverse Scattering from a Perfectly Conducting Prolate Spheroid in the Quasi-Static Domain

1973 ◽  
Vol 51 (2) ◽  
pp. 219-222
Author(s):  
D. A. Hill
Keyword(s):  
Magnetic Fields ◽  
Magnetic Dipole ◽  
Inverse Scattering ◽  
Oblate Spheroid ◽  
Prolate Spheroid ◽  
Dipole Source ◽  
Intermediate Step

The problem of inverse scattering from a perfectly conducting prolate spheroid in the quasistatic region of a magnetic dipole source is considered. From one observation of the radial and transverse scattered magnetic fields, the parameters which identify the spheroid (interfocal distance and eccentricity) are uniquely determined. The intermediate step requires the determination of the two magnetic polarizabilities. Similar results are also obtained for the oblate spheroid by a transformation.

scholarly journals Responses of dipole-source reflected shear waves in acoustically slow formations

2019 ◽  
Author(s):  
Hao Wang ◽  
Ning Li ◽  
Caizhi Wang ◽  
Hongliang Wu ◽  
Peng Liu ◽  
...  
Keyword(s):  
Finite Difference Time Domain ◽  
Dipole Source ◽  
Sh Wave ◽  
S Wave ◽  
High Fracture ◽  
S Waves ◽  
Angle Fracture ◽  
Dip Angle ◽  
Difference Time

Abstract In the process of dipole-source acoustic far-detection logging, the azimuth of the fracture outside the borehole can be determined with the assumption that the SH–SH wave is stronger than the SV–SV wave. However, in slow formations, the considerable borehole modulation highly complicates the dipole-source radiation of SH and SV waves. A 3D finite-difference time-domain method is used to investigate the responses of the dipole-source reflected shear wave (S–S) in slow formations and explain the relationships between the azimuth characteristics of the S–S wave and the source–receiver offset and the dip angle of the fracture outside the borehole. Results indicate that the SH–SH and SV–SV waves cannot be effectively distinguished by amplitude at some offset ranges under low- and high-fracture dip angle conditions, and the offset ranges are related to formation properties and fracture dip angle. In these cases, the fracture azimuth determined by the amplitude of the S–S wave not only has a $180^\circ $ uncertainty but may also have a $90^\circ $ difference from the actual value. Under these situations, the P–P, S–P and S–S waves can be combined to solve the problem of the $90^\circ $ difference in the azimuth determination of fractures outside the borehole, especially for a low-dip-angle fracture.

AMBIPOLAR DIFFUSION AND TURBULENT MAGNETIC FIELDS IN MOLECULAR CLOUDS

2011 ◽  
Vol 26 (04) ◽  
pp. 235-249 ◽  
Author(s):  
MARTIN HOUDE ◽  
TALAYEH HEZAREH ◽  
HUA-BAI LI ◽  
THOMAS G. PHILLIPS
Keyword(s):  
Magnetic Fields ◽  
Molecular Clouds ◽  
Ambipolar Diffusion ◽  
Star Forming ◽  
Star Forming Regions ◽  
Spin Interactions ◽  
Line Narrowing ◽  
Weakly Ionized ◽  
Novel Method

We review the introduction and development of a novel method for the characterization of magnetic fields in star-forming regions. The technique is based on the comparison of spectral line profiles from coexistent neutral and ion molecular species commonly detected in molecular clouds, sites of star formation. Unlike other methods used to study magnetic fields in the cold interstellar medium, this ion/neutral technique is not based on spin interactions with the field. Instead, it relies on and takes advantage of the strong cyclotron coupling between the ions and magnetic fields, thus exposing what is probably the clearest observational manifestation of magnetic fields in the cold, weakly ionized gas that characterizes the interior of molecular clouds. We will show how recent development and modeling of the ensuing ion line narrowing effect leads to a determination of the ambipolar diffusion scale involving the turbulent component of magnetic fields in star-forming regions, as well as the strength of the ordered component of the magnetic field.

scholarly journals Determination of the critical current density in the d-wave superconductor YBCO under applied magnetic fields by nodal tunnelling

2004 ◽  
Vol 17 (8) ◽  
pp. 1069-1071 ◽  
Author(s):  
Roy Beck ◽  
Guy Leibovitch ◽  
Alexander Milner ◽  
Alexander Gerber ◽  
Guy Deutscher
Keyword(s):  
Magnetic Fields ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
D Wave

Ferrofluid Convection in a Lid-Driven Cavity

2018 ◽  
Vol 388 ◽  
pp. 407-419
Author(s):  
Fatih Selimefendigil ◽  
Ali Jawad Chamkha
Keyword(s):  
Heat Transfer ◽  
Magnetic Dipole ◽  
Richardson Number ◽  
Vertical Wall ◽  
Thermal Characteristics ◽  
Dipole Source ◽  
Dipole Strength ◽  
Square Enclosure ◽  
Lower Temperature ◽  
The Right

This study numerically investigates the mixed convection of ferrofluids in a partially heated lid driven square enclosure. The heater is located to the left vertical wall and the right vertical wall is kept at constant lower temperature while other walls of the cavity are assumed to be adiabatic. The governing equations are solved with Galerkin weighted residual finite element method. The influence of the Richardson number (between 0.01 and 100), heater location (between 0.25 H and 0.75H), strength of the magnetic dipole (between 0 and 4), and horizontal location of the magnetic dipole source (between-2H and-0.5H) on the fluid flow and heat transfer are numerically investigated. It is found that local and averaged heat transfer deteriorates with increasing values of Richardson number and magnetic dipole strength. The flow field and thermal characteristics are sensitive to the magnetic dipole source strength and its position and heater location.

scholarly journals Kertsopoulos Innovation: The Three Multi-plane Polarities and the Three Interactions and Schematic Representations in the Sense of the General Cause of the Dynamic Difference

2019 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Magnetic Fields ◽  
Magnetic System ◽  
State Of The Art ◽  
Magnetic Devices ◽  
Know How ◽  
Patented Invention ◽  
Scientific Laws ◽  
First Time ◽  
Multiple Interactions

As it is known: in the state of the art, the like and the unlike polarity between two magnets remains independent of the distance between them. According to the invention: “Magnetic System of Three Interactions”, International office of patents WIPO-PCT, bearing the No WO/2013/136097of the inventor Georgios K. Kertsopoulos, the like and the unlike polarity between two magnetic constructions depends on the distance between them [1], [2], [3], [4], [5], [6], [7], [8], [9], [10]. The know-how of the invention makes it possible for interacting magnetic constructions to possess and perform interchangeable more than 96 polarities and interactions. Polarities and magnetic fields can in multiple ways interchange, depending on the varying distance between two interacting confronted magnetic constructions, offering many new variable design capabilities. For the first time, new types of poles are created, for example: simultaneous like-unlike poles or simultaneous unlike-like poles are created, causing stable or unstable balance as an interaction; also, for the first time in magnetism, new types of magnetic fields are formed never before observed, for example: remote fields of very strong attraction, without however, the contact of the magnetic constructions. The magnetic devices that perform these multiple interactions are fully patented internationally, published in a book in English, by the inventor a book in English, by the inventor [11]. The new scientific laws and principles, revealed through these experiments enrich the very basics, the foundation of magnetism, since many new types of polarities and interactions are introduced and are made possible for the first time in science and technology. In figure 1 of the article we observe the division and determination of the empty air space, between the magnetic constructions, at three distances and two boundaries which apply both for the like and the unlike front poles and in figure 2 we observe the three typical spatial distances, the three multi-plane polarities and the three interactions with properties and with spatial boundaries and interactions based on the bundles of the dynamic lines between the two magnetic constructions, on the guide, when the poles of the front poles of the arrangements are initially like. Furthermore, in figure 7 we observe a schematic representation of the three different fields (175), (177) and (178) between the above-mentioned magnetic arrangements of the constructions of the invention, with initially like front poles, in the sense of the general cause of the dynamic difference. This article is in continuation of the following published article that introduces the reader to the invention’s technology: Georgios K. Kertsopoulos (2018) Innovation article: 36 over passed restrictions of magnetism achieved by the 96 multiple magnetic polarities-interactions performed by the Kertsopoulos world patented invention vs. the known two. Advances in Nanoscience and nanotechnology [12]. https://www.opastonline.com/wp-content/uploads/2018/12/36-over-passed-restrictions-of-magnetism-achieved-by-the-96- multiple-magnetic-polarities-interactions-performed-by-the-kertsopoulos-world-ann-18.pdf?fbclid=IwAR1jYPFME5mhX2FLbKKTPAdu0YMe3FqHtoUdoRoeao8mKIp1GRuWeovEaA

Perturbation of magnetic dipole fields by a perfectly conducting prolate spheroid

Radio Science ◽  
1974 ◽  
Vol 9 (1) ◽  
pp. 71-73 ◽  
Author(s):  
David A. Hill ◽  
James R. Wait
Keyword(s):  
Magnetic Dipole ◽  
Prolate Spheroid
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