Journal of geomagnetism and geoelectricity

The Influence of Modulation Effects on Solar Flare Radiation

Robert R. BROWN

1958 Volume 10 Issue 1 Pages 1-6
Published: 1958
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.1

JOURNAL FREE ACCESS

Show abstractHide abstract

The modulation of cosmic rays at the time of the February 23, 1956 solar flare cosmic ray outburst has been estimated from the latitude variation of the cosmic ray intensity decrease observed in the period surrounding the flare event. The perturbing influence of these modulation effects on the rigidity spectrum of the flare radiation has been calculated. The change in the slope of the rigidity spectrum is found to be small as the modulation function does not have a strong dependence on rigidity between low and middle magnetic latitudes.

View full abstract

Download PDF (658K)
Magnetic Susceptibility of Orthopyroxenes

S. AKIMOTO, K. HÔRAI, T. BOKU

1958 Volume 10 Issue 1 Pages 7-11
Published: 1958
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.7

JOURNAL FREE ACCESS

Show abstractHide abstract

Magnetic properties of a series of orthopyroxenes, x FeSiO₃⋅(1-x) MgSiO₃ separated from various kinds of rocks were examined. Paramagnetic susceptibility of the orthopyroxenes was determined from the slope of the straight line part of the magnetization curve, generally expressed as σ=σ₀+χH. The following empirical formula was obtained at the room temperature for the molecular magnetic susceptibility of the orthopyroxenes with varying x, i.e. χ_mol=1.12x×10^-2e.m.u/mol. Using this experimental value and assuming that the Fe²⁺ ions are embedded isolately without any interaction between them in the orthopyroxene crystal, the effective Bohr magneton number of the Fe²⁺ ion was estimated to be 5.14 from the Curie's law. That this value is within the range of the accepted values of the ferrous ions in the crystal (5.1-5.55) seems to justify the above simple calculation.

View full abstract

Download PDF (509K)
Palaeomagnetic Researches for the Pliocene Volcanic Rocks in Central Japan (1)

Kan-ichi MOMOSE

1958 Volume 10 Issue 1 Pages 12-19
Published: 1958
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.12

JOURNAL FREE ACCESS

Show abstractHide abstract

All the rock specimens collected from middle Pliocene Komoro group and Shigarami group, have shown the marked magnetic polarisations in the direction of highly westward trend ranging roughly from N 60°W to N 110°W. The pole positions indicated by these specimens are calculated to be situated within a range from Lat. 32°N to Lat. 35°S.
A series of volcanic rocks including the middle Pliocene rock specimens above-mentioned and ranging from early Pliocene to late Pliocene, seems to indicate that the pole position would have shifted continuously from Lat. 75°N to Lat. 70°S during Pliocene times.
As far as the writer's examination goes, it should be stressed that the direction of the earth's magnetic dipole axis in Pliocene age would have shifted from the North polar region, continuously southward to the South polar region.

View full abstract

Download PDF (846K)
The Electrical Structure of Thunderstorms

Y. TAMURA, T. OGAWA, A. OKAWATI

1958 Volume 10 Issue 1 Pages 20-27
Published: 1958
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.20

JOURNAL FREE ACCESS

Show abstractHide abstract

The simultaneous observation of the thunderstorm electricity was made at eight stations during the summer of 1957. The potential-gradient changes from a number of lightning flashes were analyzed. Within the cloud, the electric moments were destroyed at the height from 4km to 7km and the values of the moments were distributed to the extent of 70Ckm. By the cloud-ground flashes, negative charges so far as about 30C were transfered to the earth through a distance from 4km to 11km. The cloud flashes and the earth flashes occurred at different horizontal positions in the cloud, as well as at different levels. Referring to the aerological data, the location of the charge center or the charge-separation level was related with the air temperature. The average results give a picture of a thunderclound similar to that of double dipole by Kuettner.

View full abstract

Download PDF (807K)
Polar Ionospheric Disturbances Associated with a Severe Magnetic Storms

Tatsuzo OBAYASHI

1958 Volume 10 Issue 1 Pages 28-35
Published: 1958
Released on J-STAGE: September 14, 2010

DOIhttps://doi.org/10.5636/jgg.10.28

JOURNAL FREE ACCESS

Show abstractHide abstract

A detailed investigation is made of a severe magnetic storm on October 28th 1951, using world-wide simultaneous geomagnetic and ionospheric data. It has been found that an outstanding electrojet stream comparatively short-lived appeared near the southern edge of the auroral zone at the end of the main phase of this storm. The ionospheric disturbance associated with this electrojet was anomalous; the electron density of the F2 layer above the electrojet stream increased suddenly to more than 10⁶ electrons per cm³ and then dropped below normal after the disappearance of the current stream.
Although any existing theory of ionospheric storms can not explain satisfactorily this anomalous change, two possible mechanisms are suggested from some consideration of the direct association of geomagnetic and ionospheric variations. One is the effect of the incomming corpuscular precipitation into the ionosphere and consequently the formation of a new F2 layer due to the increase of ionization. The other is due to the vertical drift of electrons produced by the interaction of the geomagnetic field with the currents in the F2 region returning from the main electrojet formed in the E region.

View full abstract

Download PDF (931K)

Register with J-STAGE for free!