To: “A General Solution for a Spherical Conductor in Magnetic Dipole Field”, Melvyn E. Best and Basil R. Shammas in GEOPHYSICS, v. 44, no. 4, p. 781–800 (April 1979)

Geophysics ◽  
1979 ◽  
Vol 44 (9) ◽  
pp. 1622-1622
Keyword(s):  
General Solution ◽  
Magnetic Dipole ◽  
Dipole Field ◽  
Original Version ◽  
Magnetic Dipole Field ◽  
Spherical Conductor

The authors have found an error in the paper, “A General Solution for a Spherical Conductor in Magnetic Dipole Field”, Melvyn E. Best and Basil R, Shammas in Geophysics, v. 44, no. 4, p. 781–800 (April 1979), Equation (B-9) should read as follows: [Formula: see text] (B-9) The factor [Formula: see text] was a printing error in the original version.

A general solution for a spherical conductor in a magnetic dipole field

Geophysics ◽  
1979 ◽  
Vol 44 (4) ◽  
pp. 781-800 ◽  
Author(s):  
Melvyn E. Best ◽  
Basil R. Shammas
Keyword(s):  
Magnetic Dipole ◽  
Spherical Model ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Dipole Field ◽  
First Approximation ◽  
Sulfide Ore ◽  
Magnetic Dipole Field ◽  
Airborne Em ◽  
Spherical Conductor

In electromagnetic (EM) prospecting for volcanogenic massive sulfide ore deposits, a significant number of the responses are associated with compact conductors. As a first approximation, these bodies are studied using a conducting sphere model. An exact solution is given for a spherical conductor excited by a magnetic dipole field in free space for arbitrary transmitter‐receiver (T-R) configurations with receiver positions inside or outside the conductor. In this general approach, it is possible to investigate the lateral attenuation of EM systems. In particular, the effects of flight‐line displacement from the center of the spherical conductor on several airborne EM responses are presented. For example, at normal flying heights, the standard Dighem system has a lateral attenuation 50 times larger than the EM-30 system (for a sphere of 100 m radius). Field results from the Clearwater deposit in New Brunswick are compared to the spherical model attenuations for the Dighem, Otter, and F-500 systems. The behavior of the total magnetic fields [Formula: see text] and [Formula: see text] inside the conductor are presented in the form of magnitude and phase contours. The [Formula: see text] amplitude was found to be approximately the same inside and outside the sphere; the [Formula: see text] amplitude, however, differs significantly in these two regions. Observations such as these may provide some guidance in subdividing anomalous inhomogeneities in future numerical modeling.

scholarly journals Calibration of Radiocarbon Dates for the Late Pleistocene Using U/Th Dates on Stalagmites

Radiocarbon ◽  
1997 ◽  
Vol 39 (1) ◽  
pp. 27-32 ◽  
Author(s):  
John C. Vogel ◽  
Joel Kronfeld
Keyword(s):  
South Africa ◽  
Magnetic Dipole ◽  
Satisfactory Agreement ◽  
Late Pleistocene ◽  
Calibration Curve ◽  
Dipole Field ◽  
Radiocarbon Dates ◽  
The Past ◽  
The Earth ◽  
Magnetic Dipole Field

Twenty paired 14C and U/Th dates covering most of the past 50,000 yr have been obtained on a stalagmite from the Cango Caves in South Africa as well as some additional age-pairs on two stalagmites from Tasmania that partially fill a gap between 7 ka and 17 ka ago. After allowance is made for the initial apparent 14C ages, the age-pairs between 7 ka and 20 ka show satisfactory agreement with the coral data of Bard et al. (1990, 1993). The results for the Cango stalagmite between 25 ka and 50 ka show the 14C dates to be substantially younger than the U/Th dates except at 49 ka and 29 ka, where near correspondence occurs. The discrepancies may be explained by variations in 14C production caused by changes in the magnetic dipole field of the Earth. A tentative calibration curve for this period is offered.

Kinematic Model of a Magnetic-Microrobot Swarm in a Rotating Magnetic Dipole Field

2020 ◽  
Vol 5 (2) ◽  
pp. 2419-2426 ◽  
Author(s):  
BhanuKiran Chaluvadi ◽  
Kristen M. Stewart ◽  
Adam J. Sperry ◽  
Henry C. Fu ◽  
Jake J. Abbott
Keyword(s):  
Magnetic Dipole ◽  
Kinematic Model ◽  
Dipole Field ◽  
Magnetic Dipole Field

Periodic orbits of an electric charge in a magnetic dipole field

1991 ◽  
Vol 49 (4) ◽  
pp. 327-345 ◽  
Author(s):  
Lidia Jim�nez-Lara ◽  
Eduardo Pi�a
Keyword(s):  
Periodic Orbits ◽  
Magnetic Dipole ◽  
Electric Charge ◽  
Dipole Field ◽  
Magnetic Dipole Field

Photoproduction of gravitons in a static magnetic dipole field due to currents

1978 ◽  
Vol 56 (6) ◽  
pp. 801-805 ◽  
Author(s):  
G. Papini ◽  
S. R. Valluri
Keyword(s):  
Gravitational Field ◽  
Magnetic Dipole ◽  
Cross Section ◽  
Dipole Field ◽  
Radiative Corrections ◽  
Gauge Invariant ◽  
Magnetic Dipole Field ◽  
The Cross

The cross section for the photoproduction of gravitons in magnetic dipole fields which are due to steady currents is calculated. The approach and the results are compared with the previously studied case in which no currents exist and the potential is represented by a scalar. The calculations in both cases are completely covariant and electromagnetically gauge invariant. The radiative corrections to order [Formula: see text] and [Formula: see text] in the nonrelativistic and relativistic limits are also calculated for dipole and Coulomb fields, respectively. Their evaluation is particularly simple in the transverse traceless gauge for the gravitational field.

Role of the solar main magnetic dipole field in the solar-tropospheric relations. Part I. Semiannual fluctuations in Europe

1995 ◽  
Vol 13 (4) ◽  
pp. 427-436 ◽  
Author(s):  
T. Baranyi ◽  
A. Ludmány
Keyword(s):  
Magnetic Dipole ◽  
Temperature Data ◽  
Dipole Field ◽  
The Sun ◽  
Southern Europe ◽  
Middle Latitudes ◽  
Magnetic Dipole Field ◽  
Working Mechanisms ◽  
Aa Index

Abstract. The influence of the solar corpuscular radiation on weather is demonstrated by characterizing the corpuscular impact by means of the geomagnetic aa-index and the terrestrial response by European temperature data. Considering different spatial and vectorial circumstances the following conclusions can be drawn: 1. the efficiency of the corpuscular impact depends on the Sun-Earth attitude (semiannual fluctuation); 2. this regularity depends on the polarity of the solar main magnetic dipole field; and 3. the whole complex of phenomena also depends on the geographic position - it exists at European middle latitudes but it does not exist in northern and southern Europe. We conclude that the periods of differently or oppositely working mechanisms should be separated in order to recognize the regularities.

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