On the ionospheric current system of the geomagnetic solar flare effect (s.f.e.)

An intense SFE and SSC event in geomagnetic <i>H</i>, <i>Y</i> and <i>Z</i> fields at the Indian chain of observatories

“…Volland and Taubenheim (1958), while examining SFE at the European stations between latitudes of 10°and 60°North have shown an angular di erence of 15°±30°between the SQ and SFE vectors. Veldkamp and Sabben (1960) also detected di erences between SFE and SQ vectors at European stations during the¯are on 23 March 1958.…”

Geomagnetic Effects in the Dark Hemisphere Associated With Solar Flares

“…It is now known that the occurrence of SFE is a maximum around local noon and its amplitude has a local time variation similar to that of Sq field (MCNISH, 1937;NAGATA, 1952;SUBRAHMANYAM, 1964;PINTER, 1967). Evaluation of ionospheric current systems during flare times revealed that SFE is not due to a mere augmentation of normal Sq field as thought of by CHAPMAN (1937CHAPMAN ( , 1961 and CHAPMAN and BARTELS (1940); and the current flowing layer responsible for SFE is below the normal dynamo current carrying region (VOLLAND and TAUBENHEIM, 1958;VELDKAMP and VAN SABBEN, 1960;YASHURA and MAEDA, 1961). An interpretation of SFE in terms of enhanced electrical conductivity due to solar X-ray flare flux enhancement in the band 1-20A was made by OHSHIO (1964) from a study of selected SFE events observed during I. G. Y.…”

Sq and EEJ—A Review on the Daily Variation of the Geomagnetic Field Caused by Ionospheric Dynamo Currents

“…Later studies recognized the difference in the position of the current foci between equivalent current systems of Sq and geomagnetic crochet (e.g., Volland and Taubenheim 1958;Veldkamp and Van Sabben 1960;Yasuhara and Maeda 1961;van Sabben 1961van Sabben , 1968Curto et al 1994;Gaya-Piqué et al 2008). The differences were generally attributed to the differ- Cliver and Svalgaard (2004) ent heights where the two types of ionospheric currents flow.…”