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Volume 32 (1980)
- Issue 12 Pages 721-
- Issue 11 Pages 671-
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- Issue 6 Pages 309-
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Volume 18 (1966)
- Issue 4 Pages 417-
- Issue 3 Pages 333-
- Issue 2 Pages 109-
- Issue 1 Pages 1-
Volume 18, Issue 1
Displaying 1-10 of 10 articles from this issue
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Hiroshi KAMIYAMA, Hideo TAKAKI1966 Volume 18 Issue 1 Pages 1-11
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSThe base of the iono-exosphere is defined as the level where the mean free path of ionized particles in a horizontal direction equals the scale height for the ionized gas. It is assumed that an ionized particle moving upward from this base level spirals up along a line of magnetic force without suffering any collision until it returns back to the starting base or goes across the equatorial plane and reaches its conjugate base on the other hemisphere. Due to external forces such as the gravitation, an ion with low velocity at the base can not pass across the equatorial plane but turns back at a certain point on the line of force. The critical velocity at the base for an ion which turns back at any given point on a line of force is calculated as a function of pitch angle and the magnetic latitude assuming a dipole magnetic field. Thus, ionized particles with velocities exceeding the critical velocity at the base contribute to the ion density at farther points. The computed result shows a steeper vertical gradient of the ion density at the equator than at a high latitude. The ion density at 5 earth radii in the equatorial plane is estimated to be about 9 ions cm-3.View full abstractDownload PDF (987K) -
II Ground DischargeTosio TAKEUTI1966 Volume 18 Issue 1 Pages 13-22
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSThe nature of ground discharge has been investigated using the data of electric field measurement, thunder recording, flash photographing, etc. The height of charge center neutralized by a return stroke was found not to increase with the stroke order in contrast with the report given by Malan and Schonland, instead the stroke channel was often found to progress laterally successively. The existence of a continuing discharge process between and after return stroke has been verified in agreement with the report given by Malan, and Kitagawa et al. The charge neutralized by return strokes in a ground discharge is, on the average, smaller than that neutralized by a cloud discharge. However this does not always mean that the total charge neutralized by a ground discharge is smaller than that of a cloud discharge, because a ground discharge is often accompanied by a continuing discharge process neutralizing considerable amount of negative charge. A new leader stroke which is proposed by us has the structure of corona-like streamers on the top part of the stroke channel. If the electrical structure of a thundercloud in South Africa is the same as that in Japan, the charge height reported by Malan and Schonland seems to be too high and should be reduced to a smaller value.View full abstractDownload PDF (3412K) -
S. H. WARD, D. C. FRASER1966 Volume 18 Issue 1 Pages 23-41
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSWe present, herein, formulation for the conducting permeable sphere and cylinder in an elliptically polarized alternating magnetic field. Graphically displayed are the inducing, induced, and total magnetic fields for various values of the ellipticity and azimuth of the inducing ellipse and for various values of the induction number θ=(σμω)1/2 R and permeability Km=μ2/μ1 pertaining to a sphere and a cylinder. Substantial differences can exist between inducing and resultant ellipses, measured in the horizontal plane, in the vicinity of a conductivity inhomogeneity such as a sphere or a cylinder. Additionally, a polarization ellipse appears in any vertical plane in the vicinity of an inhomogeneity.
Since substantial changes are introduced in a measured field ellipse by the presence of an inhomogeneity, these effects must be considered when induction studies of the Crust are made. Hence in the discussion we note some of the peculiarities to be expected when applying the magnetic variation, magnetotelluric and AFMAG methods.View full abstractDownload PDF (1592K) -
Folke ELEMAN1966 Volume 18 Issue 1 Pages 43-72
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSPart I. The response of standard magnetographs to earthquake waves is a seismograph effect. These instruments react as ultra-low-sensitivity seismic recorders. With little or no additional effort some magnetic observatories could be used as supplementary seismic stations at the times of great earthquakes. The effects of the Alaskan earthquake of March 28, 1964, are studied in detail in this paper. A number of similar cases are known.
Part II. Even if the response of standard magnetographs is definitely of a mechanical nature it is likely that the earthquake waves do generate real magnetic waves. Some experimental evidence (from Bergen Park, Colorado) of the existence of such waves is presented. Mechanisms for generation of the observed waves are discussed. It is shown that piezomagnetic oscillations in magnetic rock or induced currents in a region with enhanced conductivity may offer an explanation. These effects are associated with anomalous conditions in the crust. It seems evident that the properties of the “average crust” cannot explain the observed magnetic variations.View full abstractDownload PDF (4493K) -
Takesi NAGATA1966 Volume 18 Issue 1 Pages 73-80
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSThe effect of uniaxial compression (σ) upon the initial magnetic susceptibility (κ(σ)) of rocks is empirically expressed as κ(σ)=κ0/(1+βσ) where κ0 denotes the susceptibility for σ=0. This empirical relation is interpreted as due to the effect of induced magnetoelastic energy upon rotation of magnetization of magnetic minerals whose initial anisotropy axes are randomly oriented. Feasibility of theoretical results are experimentally examined using titanomagnetite samples of different grain sizes.View full abstractDownload PDF (734K) -
Takesi NAGATA1966 Volume 18 Issue 1 Pages 81-97
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSMajor characteristics of observed effects of uniaxial compression upon magnetization of rocks and assemblages of magnetic minerals are summarized as follows: -(a) uniaxial compression in a magnetic field results in a decrease of magnetization; (b) removal of the magnetic field in presence of the compession causes a decrease of remanence; (c) removal of the compression in presence of the magnetic field causes an increase of magnetization and also an increase of remanence after the magnetic field is taken off. Typical examples of experimental results are shown in Figures 2 and 3.
These observed characteristics are interpreted satisfactorily as due to an effect of increased magnetoelastic energy upon irreversible magnetization by a comparatively simple theory based on a model of an assemblage of single domains having uniaxial anisotropy, where the anisotropy energy, K, is subject to a certain distribution function n(2K/Js) with a condition dn/dK≥0.View full abstractDownload PDF (1637K) -
Naoshi FUKUSHIMA1966 Volume 18 Issue 1 Pages 99-101
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSDownload PDF (309K) -
L. SLAUCITAJS1966 Volume 18 Issue 1 Pages 103-104
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSDownload PDF (194K) -
S. A. A. KAZMI1966 Volume 18 Issue 1 Pages 105-107
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSDownload PDF (325K) -
1966 Volume 18 Issue 1 Pages e1
Published: 1966
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSDownload PDF (18K)
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