Abstract:

By analyzing the short time scale (t1 hour) power spectrum of cosmic rays observed at NM-64 Superneutron monitor at Beijing from Nov. 18/0000UT to 24/0000UT, 2001 before the severe magnetic storm with the lowest DST is-225. The analytical results show that there is no prominent period characteristic in cosmic rays power spectrum during the period form 18/0000UT to 20/0000UT. However, the 22.6154 minutes period characteristic of cosmic rays is very prominent during the period form 23/0000UT to 24/0000UT, while the other short time period characteristics are characterless which almost became noise level.

Key words: solar activity, CME, interplanetary magnetic field, cosmic rays power, spectrum of short time scale