Journal of geomagnetism and geoelectricity

Distortional Characteristics of The World-Wide Distribution and Diurnal Variation of The Ionospheric F₂ Layer Associated with The Geomagnetic Variation

Ken-ichi MAEDA

1952 Volume 4 Issue 3-4 Pages 83-93
Published: 1952
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.5636/jgg.4.83

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As the continuation of the previous report entitled “Dynamotheoretical conductivity and current in the ionosphere” (J. G. G. Vol. 4, No. 2, 1952), the effect of vertical motion of electrons on the electron density of F₂ layer is analytically treated. The vertical velocity of electrons in F₂ layer is connected to the density of horizontal dynamo current, which is obtained by solving the dynamo-theoretical equation, conserving the non-coincidence of the geographical and geomagnetic axes.
The cyclic equation giving the electron density, wherein the term representing the effect of vertical motion is included, is solved with some approximations.
The comparison of the calculated results with the observed data shows that the electron density depression and the height rise around noon near the magnetic equator, the longitudinal inequality of the latitude distribution of the noon density, and the shape of daytime variation of electron density for F₂ layer are plausibly interpreted by the present theory.

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On the Latitudinal Distribution of Maximum Values of f₀F2 in Its Diurnal Variation

T. YONEZAWA, T. SHIMAZAKI

1952 Volume 4 Issue 3-4 Pages 94-101
Published: 1952
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.5636/jgg.4.94

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Assuming that the temporal rates of electron production and removal in the F2 layer are of the forms q₀(cosχ)^m and aNⁿ, respectively, where χ is the solar zenith distance, N is the electron density, and q₀, a, m and n are constants, the latitudinal distribution of maximum values of f₀F2 in its diurnal variation has been considered, with the view of limiting the ranges of possible values for m and n. The results show that both m and n should be contained in a range roughly between 1 and 1.5, which suggests that a process of attachment type must be predominant in diminishing electron density.

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Self-Reversai of Thermo-Remanent Magnetism of Igneous Rocks (II)

T. NAGATA, S. UYEDA, S. AKIMOTO, N. KAWAI

1952 Volume 4 Issue 3-4 Pages 102-107
Published: 1952
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.5636/jgg.4.102

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By separating the test sample of Haruna pumice at 300°C, the ferromagnetic mineral grains showing self-reversal of thermo-remanent magnetism (Reverse T. R. M.) (1) were classified into three types A, AB and B. The measurement of J_s-T curve and T. R. M. characteristics of each type revealed that the sole component responsible for Reverse T. R. M. is the grains AB, each of which containing both of the constituents of types A and B in itself. It was concluded that the appearance of Reverse T. R. M. is a result of magnetic interaction between magnetic domains of the constituents A and B in the grains of type AB during cooling under a weak magnetic field.

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Development of S_D-Field with Storm-Time

Takesi NAGATA, Hironori ONO

1952 Volume 4 Issue 3-4 Pages 108-113
Published: 1952
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.5636/jgg.4.108

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That the S_D-field begins to grow up just after the sudden commencement of magnetic storm and it develops fairly intensely while the D_st-variation is still in its initial phase, is derived from a statistical examination of copies of H-, D-, and Z-traces of magnetograms at Sitka (φ_m=60°.0). A simple graphical method to represent the variation of S_D-field with storm-time is proposed.

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Influences of Ions in the Ionosphere

Teruo SATO

1952 Volume 4 Issue 3-4 Pages 114-130
Published: 1952
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.5636/jgg.4.114

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It is examined that how the propagation of radio wave in the ionized region is influenced by the positive and negative ions in its region, and how a record is altered for the wave reflected from the ionized region for these ions. Especially, these probrems are discussed for the wave in and from the lower ionized region where the ionic density is considered to be great. The equation of motion and the Maxwell's equation are solved in the presence of the earth's magnetic field, ionic and electronic collisional frequencies, including the Lorentz polarization term. Results show that (1) influences by the two kinds of ions on the propagation become greater as the frequency of the wave decreases; (2) energy of the reflection increases; (3) the deviation of energy and the virtual height of reflection for wave of certain frequency become smaller than those in the regions consisted of only electron; (4) the height of reflection thus approaches to the true height (no retardation), but the magnitude of the electron density, which is given by the relation N=Af², appears to be doubtful in the case of the measurement by low frequency radio wave.

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Propagation Characteristics of VHF over a Distance of 125km

Kunio HIRAO, Yahei UESUGI, Kazuhiko TAO

1952 Volume 4 Issue 3-4 Pages 131-140
Published: 1952
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.5636/jgg.4.131

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The statistical study of the field intensity of VHF wave over a distance of 125km was done by using mainly the observed data of 150Mc wave and partly those of 65Mc wave. For this purpose, the weather maps, the aerological data obtained at Tateno Aerological Observatory and the meteorological elements observed at Kokubunji and Hiraiso were fully investigated.
The field intensity and the range of its diurnal variation are large in summer and spring, and small in winter and on the day of precipitation. The abnormally high field intensity which appears frequently and its severe variation are considered to be reduced to the complicated distributions of the meteoroloical elements in the lower atmosphere.
The effect of front is recongnized and it seems to be more remarkable in the night than in daytime.

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Ultra Short Wave Propagation and Mirage

Madoka FUKUSHIMA, Kazuhiko TAO, Yahei UYESUGI, Kiyoshi NISHIKORI, Kuni ...

1952 Volume 4 Issue 3-4 Pages 141-146
Published: 1952
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.5636/jgg.4.141

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The observations of the field intensity of 472Mc, 153Mc and 60Mc waves and at the same time of the vertical distribution of the meteorological elements in the lower atmosphere were carried out to make claerer the anomalous propagation of VHF and UHF waves at the coast of Toyama Bay during a month in which mirage used to appear.
On the day when mirage appeared, the field intensities of shorter waves increased considerably, especially for the 472Mc wave. On the side of meteorology, the radio ducts were observed in these days and they were so intensitive as to transmit the 472Mc wave in them. From this consideration, the mirage and the radio duct are thought to be reduced to the same meteorological conditions. The results of the present study will be available to forecasting the anomalous propagotion of ultra short wave in the neighbourhood of the coastal line.

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