Title:  Study of the relation between storms and substorms in the terrestrial magnetosphere.
Author(s):  I.A. Daglis, F.-A. Metallinou (Oral)
Contact: I. A. Daglis, National Observatory of Athens, F.-A. Metallinou, University of Thessaloniki, ametal@auth.gr

ABSTRACT
Study of the relation between storms and substorms in the terrestrial magnetosphere Space storms – traditionally known as magnetic storms - are the prime complex phenomena of space  weather. The essential element of space storms in the near-Earth space environment is the ring current, which is an electric current flowing toroidally around the Earth, centered at the equatorial plane and at altitudes of ~10,000 to 60,000 km. A number  of prevailing paradigms have been driving ring current research during the past few decades; perhaps the most disputed one is the substorm build-up paradigm. Our study assesses the storm-substorm relationship through an investigation of the Dst and AL indices for a number of magnetic storms. The geomagnetic indices and ÁL are the most widely used measures of storm and substorm intensity, respectively. They are both constructed from magnetograms of ground stations, and involve deviations in the horizontal component of the geomagnetic field from quite-time values. In order to contribute to the clarification of the storm-substorm relationship, we compare the Dst and ÁL indices of a number of magnetic storms with Dst values in the range of about –300.