巻号一覧
39 巻, 3 号
選択された号の論文の5件中1～5を表示しています
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Takayuki ONO, Masaki EJIRI, Takeo HIRASAWA, Nobuyuki KAYA, Toshifumi M ...1987 年 39 巻 3 号 p. 119-128
発行日: 1987年
公開日: 2010/09/14
ジャーナル フリーThe monochromatic auroral images obtained by TV cameras in digital form make it possible to compare the spectral distribution of auroral photoemissions of active auroras with those of auroral particles measured by the EXOS-C satellite accurately. The joint data set of the monochromatic auroral images and the incoming auroral particles show that there is almost one to one correspondence between the distribution of particle precipitation and auroral photoemission. The auroral intensity ratios of I (5577Å)/I(6300Å) in an active discrete arc and in an quiet discrete arc show quite different values. The peak energies in the differential electron flux measured above these two discrete arcs agree well with the theoretical values based on the measured intensity ratios.抄録全体を表示PDF形式でダウンロード (2613K) -
Xi-shuo WANG, J. C. SAMSON, D. I. GOUGH1987 年 39 巻 3 号 p. 129-142
発行日: 1987年
公開日: 2010/09/14
ジャーナル フリーThe paper makes a new contribution to the problem of separation of magnetovariation fields, observed over a limited area of the Earth's surface, into parts of external and internal origins. It is shown that there are important advantages in making such separations in the wavenumber domain, making use of the orthogonality of external and internal parts. The method uses a unified potential both for the adjustment of data to minimize their curl, and in the separation process. The technique is tested by combining the analytically calculated fields of line currents above and below the plane of “observation”, separating them and comparing the separated field components with the known original fields. While the precision is limited by known effects of the limited area covered by the data, satisfactory correlation coefficients are obtained between separated and original fields. The new separation technique is finally applied to a magnetovariation event recorded in a recent array study in western Canada, and it is shown that a prominent anomaly is caused by internal currents.抄録全体を表示PDF形式でダウンロード (1349K) -
N. OHSHIMAN, Y. HONKURA, K. KUGE, H. SAKAI1987 年 39 巻 3 号 p. 143-158
発行日: 1987年
公開日: 2010/09/14
ジャーナル フリーObservations of the geomagnetic total intensity, electric self-potential and surface resistivity were carried out at the Atotsugawa fault, a 60km long active fault of strike-slip type located in central Japan, in order to investigate the active fault structure and fault activity from electric and magnetic aspects. Notable anomalies were found along a measurement line selected in the central segment of the Atotsugawa fault. The anomalies are summarized as follows. The surface resistivity, as derived from VLF-MT, of the zone bounded on the north by one fault line and on the south by another is lower than that outside the zone. A very local anomaly in self-potential exists at the northern fault line which constitutes the northern boundary of the low resistivity zone. Inside this low resistivity zone exists a somewhat more resistive body. It should be highly magnetized as deduced from a magnetic anomaly amounting to about 600nT which was observed over the resistive body. The low resistivity zone seems to correspond to the fractured zone bounded by the two fault lines, and the northern one would be more active as implied by the self-potential anomaly which can be interpreted in terms of the electrokinetic effect associated with groundwater flow along the fault plane.抄録全体を表示PDF形式でダウンロード (1330K) -
Wataru MIYAKE, Toshihumi MUKAI, Kiyohumi YUMOTO, Takao SAITO, Kunio HI ...1987 年 39 巻 3 号 p. 159-164
発行日: 1987年
公開日: 2010/09/14
ジャーナル フリーPDF形式でダウンロード (633K) -
Heikki NEVANLINNA1987 年 39 巻 3 号 p. 165-174
発行日: 1987年
公開日: 2010/09/14
ジャーナル フリーThe spatial power spectrum of the geomagnetic field was analyzed by calculating the spectrum for the X, Y and Z components separately. Based on different slopes of the power spectrum lines it was concluded that the dipole field originates partly from the surface layer of the outer core partly from the inner core. The dipole field from the inner core is axially symmetric.
A new method was introduced for separating the drifting and non-drifting parts in the spatial power spectrum of secular variation. Equations were derived which connect the non-drifting part with the energy density spectrum.
The non-drifting part has been rather stable since 1965. In the drifting part the harmonic constituents n=1 and n=4 have increased roughly by a factor five during the last 20 years.抄録全体を表示PDF形式でダウンロード (837K)
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