PROBLEMS OF GEOCOSMOS

Proceedings of the 7th International Conference "Problems of Geocosmos" (St. Petersburg, Russia, 26-30 May 2008)
Figure 3. Auroral oval and SEP penetration boundary cross-sections
The Earth's internal magnetic field model was used to calculate L coordinate. However the
magnetospheric currents can significantly change the equatorial footprint location. The last column of the
Table 1 represents the distance to the equatorial footprint of the magnetic field line mapped from ionosphere
to the equatorial plane by paraboloid model of the magnetospheric magnetic field (Alexeev et al., 2001). The
"real" L , values differ from "classical" significantly, depending on longitude and MLT. Figure 4 shows the
magnetic field lines calculated by IGRF (green line) and paraboloid (red line) models at 6:43 UT 15.5.2005.
We can see that magnetospheric currents shift magnetic field lines to the night side. From the other hand, we
can see from the Table 1 that during all the chosen time moment penetration boundary lies on the closed
magnetic field lines, though before the storm and during recovery this is region adjacent to polar cap, while
during storm main phase this is region of trapped radiation.
Table. 1.
MM HH Jp 1-5
MeV
MLT LAT LON MLAT MLOM L(exp) L(calc)
BEFORE THE STORM
14 5 21.2487 430.0 15.979 55.195 -76.813 66.469 -10.03 6.29 6.04
14 5 21.4749 706.9 3.011 69.539 68.219 60.125 152.00 5.45 4.06
15 5 0.3263 920.5 14.985 61.305 -120.219 66.984 -71.14 6.98 6.1
15 5 0.5331 622.6 3.849 67.945 23.781 64.672 118.81 5.66 5.4
MAIN PHASE
15 5 6.4348 97.9 15.716 62.867 148.594 53.297 -151.72 3.44 2.8
15 5 6.7274 174.6 3.08 46.82 -58.781 57.953 14.28 3.28 3.5
RECOVERY PHASE
16 5 3.7991 19.9 15.018 65.117 -172.125 60.633 -123.03 4.63 4.2
16 5 4.0287 26.5 3.615 59.758 -25.078 66.578 63.078 4.47 6.2
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