Properties of the Main Phases of the Super Geomagnetic Storms (ΔSYM-H ≤ −250 nT) with Different Heliolongitudes

Abstract

We studied the properties of the main phases of 24 super geomagnetic storms (SGSs) (ΔSYM-H ≤ −250 nT) since 1981. We divided the SGSs into two subgroups: SGSs-I ( −400 nT< ΔSYM-H ≤ −250 nT) and SGSs-II (ΔSYM-H ≤ −400 nT). Of the 24 SGSs, 16 are SGSs-I and 8 are SGSs-II. The source locations of SGSs were distributed in the longitudinal scope of [E37, W66]. 95.8% of the SGSs were distributed in the longitudinal scope of [E37, W20]. East and west hemispheres of the Sun had 14 and 10 SGSs, respectively. The durations of the main phases for 6 SGSs ranged from 2 h to 4 h. The durations of the main phases for the rest 18 SGSs were longer than 6.5 h. The duration of the SGSs with source locations in the west hemisphere varied from 2.22 h to 19.58 h. The duration for the SGSs with the source locations in the east hemisphere ranged from 2.1 h to 31.88 h. The averaged duration of the main phases of the SGSs in the west and east hemispheres are 8.3 h and 13.98 h, respectively. |ΔSYM-H/Δt| for 6 SGSs with source locations distributed in the longitudinal area ranging from E15 to W20 was larger than 1.0 nT·min-1, while |ΔSYM-H/Δt| for the rest 18 SGSs was lower than 1.0 nT·min-1. |ΔSYM-H/Δt| for SGSs-I varied from 0.18 nT·min-1 to 3.0 nT·min-1. |ΔSYM-H/Δt| for 8 SGSs-II varied from 0.37 nT·min-1 to 2.2 nT·min-1 with 7 SGSs-II falling in the scope from 0.37 nT·min-1 to 0.992 nT·min-1.

Properties of the solar wind parameters associated with the enhanced Russell-McPherron Effect in March 2008

“…However, the enhanced R-M effect described by the enhanced by the ring current effect influenced by the solar wind dynamic pressure has not been reported. It has been found that the ring current effect caused by the solar wind during a period should be indicated by ∆SYM-H rather than by the minimum of the SYM-H index (Zhao, Le, and Liu, 2023).…”