Anisotropy Analyses of Cosmic Ray Before the Geomagnetic Storm on Sep. 24, 1998

Cosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90\% of all the incoming cosmic ray particles are protons, about 9\% are helium nuclei and about 1\% are electrons. The nuclei that make up cosmic rays are able to travel from their distant sources to the Earth because of the low density of matter in space. Nuclei interact strongly with other matter, so when the cosmic rays approach Earth they begin to collide with the nuclei of atmospheric gases. These collisions, in a process known as shower, result in the production of many pions and kaons, unstable mesons which quickly decay into muons. Muons are ionizing radiation, and may easily be detected by many types of particle detectors such as bubble chambers or scintillation detectors. Based on the muon measurement data of 30°, 49°, 64° of East, West, South, North components of cosmic ray from Nagoya station, the north-south and west-east anisotropy of cosmic ray just before geomagnetic disturbances and quiet days is analyzed by use of Haar wavelet. It was found that fluctuations of the anisotropy of cosmic ray before geomagnetic disturbances increased due to the approaching of CME because the shock front and strong IMF induced by CME and the coefficient of wavelet always increased monotonously more than 10 hours ahead the geomagnetic storm, which hopefully could be the premonitory properties of the eruption of severe geomagnetic storm.