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[en] In the original publication of this article , some reference lines are missing in Fig. 5a and Fig. 6b(6). This correction shows the correct figures. The publisher apologizes to the readers and authors for the inconvenience.
[en] The Regions 1 and 2 Birkeland current patterns in the ionosphere can be idealized as two nearly concentric, bipolar circles or rings. The Region 1 ring is electrically connected to the outer (or poleward) boundary of the plasma sheet and the Region 2 ring to its inner (or equatorward) boundary. The physics governing the radii of these two rings are therefore different. In particular, in the absence of substorms, the rate of change of the radius of the Region 1 ring is proportional to the polar cap potential, but the rate of change of the radius of the Region 2 ring is proportional to the rate of change of the polar cap potential. Thus, the rates of growth and decay of the radii of these rings will in general be different. Calculation shows that during dayside merging intervals, Ring 1 expands about 16 times faster than Ring 2. Under typical merging potentials, Ring 1 will cross the initial ring separation in about 1 hour. Situations are identified in which the circles approach very near to each other (or actually attempt to cross each other) as necessitating the onset of a substorm to cause a sudden reduction in the radius of the inner ring. Thus, the rings, which would otherwise be nearly independent of each other, are instead strongly coupled by the substorm process. The theory predicts the common radius of the coupled ring system (approximately 19 degrees to 22 degrees) and its dependence on the cross-polar-cap potential (approximately phi 0.2). 23 references
[en] Complete text of publication follows. High-resolution geomagnetic field data (i.e., ≤5 seconds) have recently become more commonly used by space physicists. The data permit the identification of Pi2 pulsations, having periods of 40-150 seconds and irregular waveforms. Pulsations of this type appear clearly in time series from mid- and low-latitude ground stations on the nightside at substorm onset. Therefore, with data from multiple observatories, substorm genesis and evolution can be monitored. Here we propose a new substorm index, the Wp index (Wave and planetary), which measures Pi2 spectral power at low-latitude. This index is derived from geomagnetic field data obtained from observatories arranged in longitude around the Earth's circumference. Presently, data from 8 ground stations (Kakioka, Urumqi, Iznik, Fuerstenfeldbruck, San Juan, Teoloyucan, Tucson, and Honolulu) are used, but future work will include data from other sites as well (Tristan da Cunha and Ebro). Here we compare substorm occurrence estimated from the Wp index and those from the AE and ASY indices. We show that the Wp index is a good indicator of substorm onset. The Wp index, other substorm indices, and geosynchronous satellite data are plotted in a stack and are made available from the web site (http://s-cubed.info) for public use.
[en] As a result of spectrophotometric observations at the Yakutsk meridian are revealed the next substorm manifestations in the luminescence dynamics: increasing of brightness the diffuse auroral zone simultaneously with beginning of explosive phase activation; its equatorial expansion to the region of the SAR-arc; stepped amplification of night sky emissisons at latitudes of the SAR-arc projection; development of luminescence pulsations during the phase of substorm restoration
[en] 10.12 1988 disturbed period from 14 up to 20 LT (45 deg E time) with two typical substorms, 14.30-15.30 and 18.30-19.30 LT and with magnetic variation between 15.10 and 18.30 LT, stand out at the background of the quiet magnetic field of the first half of Dec 1988
[en] Ionospheric effects of substorms are considered using the networks of the vertical probing stations during SUNDIAL periods. Calculations of electron concentration distribution and comparison of calculation results with experimental data are conducted on the basis of the developed technique of simulation of large-scale internal gravitational wave effects