Hist. Geo Space Sci., 5, 81–134, 2014 www.hist-geo-space-sci.net/5/81/2014/ doi:10.5194/hgss-5-81-2014 © Author(s) 2014. CC Attribution 3.0 License. Investigations of the auroral luminosity distribution and the dynamics of discrete auroral forms in a historical retrospective Y. I. Feldstein1, V. G. Vorobjev2, V. L. Zverev2, and M. Förster3 1Institute of Terrestrial Magnetism, Ionosphere, and Radiowave Propagation of the Russian Academy of Sciences (IZMIRAN), 142090 Troitsk, Moscow region, Russia 2Polar Geophysical Institute, Apatity, Murmansk region, 184209, Russia 3GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, 14473 Potsdam, Germany Correspondence to: Y. I. Feldstein (
[email protected]) Received: 18 December 2013 – Revised: 17 March 2014 – Accepted: 16 April 2014 – Published: 21 May 2014 Abstract. Research results about planetary-scale auroral distributions are presented in a historical retrospective, beginning with the first “maps of isochasms” – lines of equal visibility of auroras in the firmament (Fig. 2) – up to “isoaurora maps” – lines of equal occurrence frequency of auroras in the zenith (Fig. 4). The exploration of auroras in Russia from Lomonosov in the 18th century (Fig. 1) until the start of the International Geophysical Year (IGY) in 1957 is shortly summed up. A generalised pattern of discrete auroral forms along the auroral oval during geomagnetically very quiet intervals is presented in Fig. 5. The changes of discrete auroral forms versus local time exhibit a fixed pattern with respect to the sun. The auroral forms comprise rays near noon, homogeneous arcs during the evening, and rayed arcs and bands during the night and in the morning.