A PROPOSED METHOD OF MEASURING THE DERIVATIVES OF THE EARTH’S MAGNETIC FIELD

Geophysics ◽  
1943 ◽  
Vol 8 (1) ◽  
pp. 23-31
Author(s):  
J. H. Jones
Keyword(s):  
Magnetic Field ◽  
Angular Speed ◽  
Initial Permeability ◽  
High Rate ◽  
Secondary Coil ◽  
Earth’S Magnetic Field ◽  
Rate Of Increase ◽  
Earth's Magnetic Field ◽  
Derivatives Of ◽  
Magnetizing Field

The method of measuring the derivatives of the earth’s magnetic field which is proposed depends on the fact that a small steady magnetic field will modify the e.m.f. induced in the secondary coil of a detector with a core of magnetizable material possessing high initial permeability and a high rate of increase of the permeability with the strength of the magnetizing field. It is shown that a detector of this type is equivalent to an inductor coil rotating with angular speed equal to the periodicity of the alternating magnetizing field.

scholarly journals The Earth's magnetic field in Southern Africa at the epoch, 1 July 1930

1947 ◽  
Vol 240 (818) ◽  
pp. 251-294 ◽  
Keyword(s):  
Magnetic Field ◽  
High Rate ◽  
Earth’S Magnetic Field ◽  
Magnetic Elements ◽  
Magnetic Inclination ◽  
Actual Observation ◽  
Earth's Magnetic Field ◽  
South West Africa ◽  
Linear Manner ◽  
The Magnetic Field

This paper is an attempt to determine the earth’s magnetic field in that part of Africa lying to the south of the Zambesi and Kunene Rivers, at the epoch 1930-50. The data used are: (1) Measurements made at about seven hundred stations by a number of previous workers, during the period 1900 to 1925, and already published. (2) Observations at about fifty of these stations made by the present writer between 1928 and 1930. These have been used to determine the secular variation, and thus to deduce the 1930-50 values of the magnetic field at all the other stations. The magnetic inclination is found to have changed in an almost linear manner, the maximum rate occurring in South-West Africa. The horizontal intensity has diminished at a gradually increasing rate, the maximum change being near Cape Town. The declination appears to have varied at a high rate until about 1928, and much more slowly since then. The greatest total changes are found near Durban. The results are presented in the form suggested by Ljungdahl. Maps with highly smoothed isomagnetic lines are used to show the probable ‘normal’ values of three magnetic elements (declination, inclination, and horizontal intensity), i.e. the component of the field not due to local magnetic disturbance. At each point of actual observation is placed a symbol indicating to what extent the observed value differs from that obtained by interpolation between the isomagnetic lines.

The Atlas of the Earth's Magnetic Field

2012 ◽  
Author(s):  
A. Soloviev ◽  
A. Khokhlov ◽  
E. Jalkovsky ◽  
A. Berezko ◽  
A. Lebedev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Earth’S Magnetic Field ◽  
Earth's Magnetic Field

Atlas of Earth's magnetic field

2011 ◽  
Vol 12 (2) ◽  
pp. 1-9
Author(s):  
A. E. Berezko ◽  
A. V. Khokhlov ◽  
A. A. Soloviev ◽  
A. D. Gvishiani ◽  
E. A. Zhalkovsky ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Earth’S Magnetic Field ◽  
Earth's Magnetic Field

scholarly journals Night-time Sferic Propagation at Frequencies Below 10 KHz

1967 ◽  
Vol 20 (1) ◽  
pp. 101 ◽  
Author(s):  
KJW Lynn ◽  
J Crouchley
Keyword(s):  
Magnetic Field ◽  
Geographic Distribution ◽  
Angle Of Incidence ◽  
European Studies ◽  
Earth’S Magnetic Field ◽  
Night Time ◽  
The West ◽  
Earth's Magnetic Field ◽  
Effective Angle

Results of a study at Brisbane of individual night-time sferics of known origin are described. A propagation attenuation minimum was observed in the 3-6 kHz range. The geographic distribution of sferic types was also examined. Apparent propagation asynunetries were observed, since sferics were detected at greater ranges to the west than to the east at 10 kHz, whilst the number of tweek-sferics arising from the east was about four times that arising from the west. Comparison with European studies suggest that these asymmetries are general. These results are then " interpreted in terms of an ionospheric reflection cgefficient which is a function of the effective angle of incidence of the wave on the ionosphere and of orientation with respect to the Earth's magnetic field within the ionosphere.

Low absolute paleointensity during Late Miocene Noma excursion of the Earth’s magnetic field

2019 ◽  
Vol 287 ◽  
pp. 10-20 ◽  
Author(s):  
Kazuhiro Okayama ◽  
Nobutatsu Mochizuki ◽  
Yutaka Wada ◽  
Yo-ichiro Otofuji
Keyword(s):  
Magnetic Field ◽  
Late Miocene ◽  
Earth’S Magnetic Field ◽  
Earth's Magnetic Field

Directions and intensities of the Earth’s magnetic field during a reversal: results from the Permo-Triassic Siberian trap basalts, Russia

2004 ◽  
Vol 218 (1-2) ◽  
pp. 197-213 ◽  
Author(s):  
Christoph Heunemann ◽  
David Krása ◽  
Heinrich C Soffel ◽  
Evguenij Gurevitch ◽  
Valerian Bachtadse
Keyword(s):  
Magnetic Field ◽  
Earth’S Magnetic Field ◽  
Siberian Trap ◽  
Earth's Magnetic Field

Two-dimensional NMR spectroscopy in Earth’s magnetic field

2006 ◽  
Vol 182 (2) ◽  
pp. 343-347 ◽  
Author(s):  
Jeremy N. Robinson ◽  
Andrew Coy ◽  
Robin Dykstra ◽  
Craig D. Eccles ◽  
Mark W. Hunter ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Nmr Spectroscopy ◽  
Two Dimensional ◽  
Earth’S Magnetic Field ◽  
Earth's Magnetic Field
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