Correspondence of a global isolated substorm to the McPherron statistical model

  1. Baikal State University, Irkutsk, Russia
  2. Institute of Solar-Terrestrial Physics SB RAS, Irkutsk, Russia
  3. Institute of Astronomy and Geophysics AS Mongolia, Ulaan-Baatar, Mongolia
  4. Institute of Cosmophysical Research and Radio Wave Propagation FEB RAS, Paratunka, Russia
  5. Sodankyla Geophysical Observatory, University of Oulu, Sodankyla, Finland
  6. Polar Geophysical Institute RAS, Apatity, Russia

It is shown that a diamagnetic structure (DS) of the slow solar wind (SW), the source of which on the Sun was a chain of streamers, arrived at Earth’s orbit on December 22, 2015. It interacted with Earth’s magneto-sphere under conditions when the northward Bz component of the interplanetary magnetic field (IMF) remained for a long time in preceding undisturbed SW. The interaction and a sharp change in the direction of Bz to the south gen-erated an isolated substorm whose duration depends on the duration of interaction with the DS. The substorm began at midday with the passage of the DS into the magnetosphere and spread to the east. All phases of the substorm — growth, expansion, and recovery — were observed for two hours. Variations in the SW and IMF parameters are shown to coincide for the isolated substorm whose energy source was the slow solar wind DS, and a trigger was the abrupt change in the direction of the vertical IMF compo-nent from north to south. The coincidence is justified by statistical generalizations of the same parameters in 40% of cases of long-term observations of individual substorms whose trigger was a change in Bz direction.

Solar-Terrestrial Physics. - 2022. - №. 2. - pp. 37-46.