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The cosmic ray increases due to considerable depressions of cosmic ray cut off rigidity during large geomagnetic storms are investigated.Data from 11 superneutron monitors in world network are analyzed for six geomagnetic storms of various type during 1984-1989.The results show that the storm-time increases are due to existence of westward equatorial ring currents developing or intensifying during geomagnetic storms.The stronger the geomagnetic storm,the larger the storm-time increase.The storm-time increases... The cosmic ray increases due to considerable depressions of cosmic ray cut off rigidity during large geomagnetic storms are investigated.Data from 11 superneutron monitors in world network are analyzed for six geomagnetic storms of various type during 1984-1989.The results show that the storm-time increases are due to existence of westward equatorial ring currents developing or intensifying during geomagnetic storms.The stronger the geomagnetic storm,the larger the storm-time increase.The storm-time increases have obvious latitude effect or geomagnetic cut off rigidity dependence.Beijing station is at the obvious region for the storm-time increase,and storm-time increases are of local tune dependence.This enhancement is larger at the daytime than at the nighttime.Showing that the intensifying ring current is asymmetrical. 利用11个地面超中子堆的资料分析了6个不同地磁暴期间由于赤道环电流增强引起的暴时增加,并分析了它们的特征。结果表明,地磁暴愈强,暴时增加愈明显。暴时增加与地磁H分量的变化有很好的负相关,并有明显的纬度效应或与地磁截止刚度有依赖关系。北京地区是暴时增加相当明显的区域。暴时增加还有明显的地方时依赖关系。在白昼一侧的增加更大,表明环电流具有不对称性的特征。 A solar cosmic rays Ground Level Enhancement(GLE) event associated with a X7.1/2b solar flare in 2005 January 20 was observed by the Yangbajing solar neutron telescope(SNT) and neutron monitor(NM), located at Yangbajing Tibet(90.53°E, 30.11°N, 4310m a.s.l) with the highest vertical geomagnetic cut-off rigidity of 14.1GV in NM network. The statistical significance of the counting rate enhancement recorded by solar neutron telescope in >40MeV channel was 3.7σin the time window of 07:00-07:05UT and 6.0a in the... A solar cosmic rays Ground Level Enhancement(GLE) event associated with a X7.1/2b solar flare in 2005 January 20 was observed by the Yangbajing solar neutron telescope(SNT) and neutron monitor(NM), located at Yangbajing Tibet(90.53°E, 30.11°N, 4310m a.s.l) with the highest vertical geomagnetic cut-off rigidity of 14.1GV in NM network. The statistical significance of the counting rate enhancement recorded by solar neutron telescope in >40MeV channel was 3.7σin the time window of 07:00-07:05UT and 6.0a in the time window of 07:00-07:20UT, respectively. The onset time of 06:51-06:52UT for this GLE event was clearly observed by the Yangbajing NM. Our observation indicates that solar protons have been accelerated up to energies of > 10GeV during this solar event. 西藏羊八井位于东经90.53°,北纬30.11°,海拔4310m,垂直地磁截止刚度14.1GV.2005年1月20日羊八井太阳中子望远镜和中子监测器探测到与X7.1/2b太阳耀斑相关的GLE事件,其中太阳中子望远镜能量>40MeV的能道在5min(07:00-07:05UT)和20min(07:00-07:20UT)的时间间隔内计数率增长的统计显著性分别是3.7σ和6.0σ,同时羊八井中子监测器也探测到计数率的增长,初始时间为06:51-06:52UT.观测表明在这次GLE事件中太阳质子可被加速到能量大于10GeV.
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