The magnetic local time (MLT) dependence of magnetic variations on the ground at mid-latitudes caused by field-aligned currents is estimated for two cases where the distribution of the field-aligned ...currents is defined at the magnetosphere and at the polar ionosphere. The results show that the MLT distribution of the magnetic variations shifts eastward or westward by a few hours in the latter case because the terrestrial magnetic field declines from the geographic meridian. Whether the distribution shifts eastward or westward depends on the longitude of the observatory. This fact suggests that whether the distribution of a phenomenon propagating along the terrestrial magnetic field is mainly determined in the magnetosphere or in the ionosphere may be determined by comparing the MLT distribution of the phenomenon's magnetic effect at observatories located at various longitudes.
Space Weather Information Network on JGNII Watari, Shinichi; Murata, Takeshi; Ogino, Tatsuki ...
Journal of the National Institute of Information and Communications Technology,
09/2005, Letnik:
52, Številka:
3-4
Journal Article
The space weather covers information over a vast area such as the Sun, interplanetary space, magnetosphere, and ionosphere. It is a problem how to handle distributed databases of various data and how ...to communicate among distributed researchers. This report introduces one attempt to use high-speed network JGI\111.
Ring Current Response to Impulsive Southward IMF TAKAHASHI, Shun; IYEMORI, Toshihiko; TAKEDA, Masahiko
Journal of geomagnetism and geoelectricity,
1990, 1990-00-00, Letnik:
42, Številka:
11
Journal Article
Odprti dostop
We simulate particle motions in a realistic magnetospheric model under an impulsive dawn-dusk electric field and show an oscillation of the ring current intensity. This oscillation is caused by the ...effect of the asymmetric configuration of magnetospheric magnetic field. It is suggested that this effect explains the second development of the Dst often observed during recovery of storms after an impulsive southward IMF or in the impulse response function of the Dst to the IMF southward component.
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.
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