Abnormality of GCR intensities measured by ground NMs in solar minimum of solar cycles 23/24

  • Lee, Eo-Jin (Astronomy & Space Science, Chungnam National Univ.) ;
  • Yi, Yu (Astronomy & Space Science, Chungnam National Univ.)
  • Published : 2009.10.15

Abstract

Many solar, interplanetary and geomagnetic activity parameters have 11-year cycle on the average in sync with solar sunspot number. The galactic cosmic ray (GCR) intensity measured by ground Neutron Monitor (NM) is one of those parameters showing the unprecedented activity levels in the current solar minimum (2008-2009) of solar cycles 23/24. We defined abnormality as the ratio of deviation from long term mean over mean amplitude of solar cycle change. The abnormality distribution map was drawn using all the data of NM stations available online. The implications of those unprecedented levels of GCR intensities of different cutoff rigidities will be discussed.

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