Journal of geomagnetism and geoelectricity

World-wide Distribution of Cosmic-Ray Neutron Intensity at Sea Level

Masahiro KODAMA

1959 Volume 10 Issue 2 Pages 37-46
Published: 1959
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.37

JOURNAL FREE ACCESS

Show abstractHide abstract

The world-wide distribution of cosmic ray intensity at sea level was decided from the several latitude surveys so far carried out by many researchers. The contour map thus obtained was compared with the various models for the earth's geomagnetic field.

View full abstract

Download PDF (1076K)
An Experimental Proof of the Mode Theory of VLF Ionospheric Propagation

T. OBAYASHI, S. FUJII, T. KIDOKORO

1959 Volume 10 Issue 2 Pages 47-55
Published: 1959
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.47

JOURNAL FREE ACCESS

Show abstractHide abstract

A new spectoscope recording continuously the amplitude-frequency spectrum of VLF atmspherics has been developed. The receiver sweeps the frequency giving complete coverage of the band of 5-70kc/s repeatedly and the output is displayed on an intensity modulated cathode-ray tube, which is photographed on a slowly moving film.
Observations have been carried out and it appears that the result provides an excellent experimental base for the mode theory of VLF ionospheric propagation. It is found that the frequency-spectrum of distant atmospherics shows a broad intensity maximum around 10kc/s and decreases its intensity towards higher frequencies with undulating peaks. Marked selective absorption bands appeared in the spectrum are variable according to the time of day, and they might be assoiated with cut-off frequencies of the waveguide bounded by the earth and the ionosphere. The solar flare effect on VLF atmospherics propagation is also revealed, which indicates a sudden shift of the spectrum to higher frequencies owing to the increase of ionization and the lowering of a reflecting height of the ionosphere.

View full abstract

Download PDF (1320K)
The Absolute Measurement of the Concentrations of the Radioactive Substances in the Atmosphere, in Tokyo

M. KAWANO, S. NAKATANI

1959 Volume 10 Issue 2 Pages 56-63
Published: 1959
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.56

JOURNAL FREE ACCESS

Show abstractHide abstract

Comparing with the already known concentration of radon emanated from the radium standard solution, the absolute measurement of the concentrations of the radioactive substances in the atmosphere was carried out by the ionization chamber method. The concentrations of the radioactive substances in the atmosphere were 2.3-12.0×10^-16C/cm³ on fine days.
The ratio of the ionization current by beta-, gamm-raditions to that by total radiations in the air of definite volume is about 5-25 percent, and is very larger than that in radon being in the state of radioactive equilibrium with its decay products (the ratio is about 2-3 percent).

View full abstract

Download PDF (800K)
Latitude Variation of Cosmic Ray Intensity Decreases at Sea-Level

Robert R. BROWN

1959 Volume 10 Issue 2 Pages 64-65
Published: 1959
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.64

JOURNAL FREE ACCESS

Download PDF (221K)
On the Geomagnetic Sd Field

Hiroshi MAEDA

1959 Volume 10 Issue 2 Pages 66-68
Published: 1959
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.66

JOURNAL FREE ACCESS

Download PDF (313K)

Register with J-STAGE for free!