巻号一覧
31 巻, 1 号
選択された号の論文の4件中1～4を表示しています
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Toshihiko IYEMORI, Hiroshi MAEDA, Toyohisa KAMEI1979 年 31 巻 1 号 p. 1-9
発行日: 1979年
公開日: 2010/03/12
ジャーナル フリーThe impulse response of the geomagnetic indices (Dst, AL, AU and AE) to the interplanetary magnetic field southward component (IMF-Bz) is calculated on the assumption that the magnetosphere acts as a linear system. Hourly data for 300 days are used in this analysis. The main results obtained are as follows: (1) Using interplanetary data, a fairly large portion of geomagnetic disturbances may be predicted with the assumption of a linear system. (2) The response of the Dst index and the AL index develops at two steps or has an oscillating property with a period of several hours. (3) The response of the AU index is rather different from that of the other indices. These results may suggest that the disturbances represented by the Dst and AL indices have a common origin associated with the interplanetary magnetic or electric field, whereas those indicated by the AU index have an origin somewhat different from it.抄録全体を表示PDF形式でダウンロード (805K) -
Koh-ichiro OYAMA, Kunio HIRAO1979 年 31 巻 1 号 p. 11-19
発行日: 1979年
公開日: 2010/03/12
ジャーナル フリーThis paper reports a localized hot electron layer which was discovered in the ionospheric dynamo region over the Kagoshima Space Center, Japan. The appearance of such a layer was restricted to around 11hr in LT in winter. The maximum electron temperature in the layer was controlled by the sunspot number, the intensity of the dynamo current and the location of the focus of the geomagnetic Sq current vortex. In the first half of this paper, the morphology of the phenomenon is described in detail and in the second half a mechanism is suggested for the layer formation.抄録全体を表示PDF形式でダウンロード (788K) -
Akira SUZUKI1979 年 31 巻 1 号 p. 21-46
発行日: 1979年
公開日: 2010/03/12
ジャーナル フリーEquivalent current systems of the daily geomagnetic variations are drawn for every two hours throughout the month, December 1964, to investigate universal-time (UT) and day-to-day variations in the middle and low latitude regions. It is confirmed that there co-exist two types of UT variations in the current systems, the regular and the occasional ones. It is also found that the UT variations in the intensities of the northern and southern current vortices are generally in the opposite sense for both the external and internal current systems, though they are sometimes in the same sense. The centers of the northern and southern vortices move in the same direction, coming most northwards at about 10-12h UT and most southwards at about 02-04h UT. The harmonic coefficients of the geomagnetic variation show a periodic change with UT, in accordance with the regular UT-dependence of Sq on quiet days. The day-to-day changes at fixed UT's in the intensity and position of the current systems depend systematically on UT. These and other results obtained are discussed in relation to the origin of the regular and occasional variations in the equivalent current systems.抄録全体を表示PDF形式でダウンロード (2241K) -
Hiroshi OYA, Akira MORIOKA1979 年 31 巻 1 号 p. 47-66
発行日: 1979年
公開日: 2010/03/12
ジャーナル フリーOn Oct. 20, 1974, a successful observation of the Jovian decameter wave emissions started at Mt. Zao observatory, of Upper Atmosphere and Space Research Laboratory, Tohoku University, using two-element Yagi antennas. In addition to the intensity measuring system, interferometric observations of the decameter waves with two-element Yagi antennas of 40m spacing started on Dec. 6, 1975. The source position of the arriving decameter waves is identified by sweeping the beam direction using a newly developed variablephase system where the phase difference between the two antennas is swept artificially through the electronic circuits. The results give a confirmation that the decameter waves arrive at the antenna starting from Jupiter.
The observation of the decameter waves has provided the data that give an identification of the main and the early sources of the Jovian decameter wave emissions; it is also reconfirmed that the early source emissions are controlled by the position of To while no such remarkable effects are detected for the emission from the main source.抄録全体を表示PDF形式でダウンロード (4286K)
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