【摘要】 在雷暴电场的偏转作用下,宇宙线次级粒子到达探测面的位置将受到影响,其横向分布也将发生变化。本文采用Monte Carlo方法,研究雷暴期间LHAASO观测面（海拔约4400 m）宇宙线次级粒子横向分布的变化。结果表明,雷暴期间次级粒子的横向分布将变宽,其变化幅度与电场强度有关,与天顶角、原初能量也有很强的依赖关系。在–1700 V·cm^–1的电场中,次级粒子横向分布的变化幅度在天顶角0°时为3.8%,天顶角50°时为34%;当原初能量约180 GeV时,次级粒子横向分布的变化幅度为9.9%,原初能量约560 TeV时,其变化幅度高达119%。本文的模拟结果可为理解雷暴电场偏转宇宙线次级粒子的物理机制、雷暴期间LHAASO中宇宙线数据的变化规律提供信息。更多还原

【Abstract】 The charged components of cosmic ray secondary particles are deflected by thunderstorm electric fields as they pass through kilometer-scale thunderclouds. As a result, the information on location of secondary particles reaching the observation level will be affected, and the lateral distribution will also be changed. In this paper, the Monte Carlo method is used to simulate the effects of near-earth thunderstorms electric field on the lateral distribution of secondary particles at LHAASO. A vertical and uniform atmospheric electric field model is used in our simulations. The results show that during thunderstorm the lateral distribution of secondary particles widens, and the variation amplitude is not only associated with the strength of electric field, but also dependent upon the primary energy and zenith angle of cosmic rays. In an electric field of –1000 V·cm^–1（below the threshold of the Relatively Runaway Electrons Avalanche, RREA）, the variation amplitude of the lateral distribution of secondary particles is about 0.7% for θ=0° and the variation amplitude reaches 4.7% for θ=50°. The primary energy of cosmic rays is about 180 GeV, the increasing amplitude is about 0.6%. When the primary energy is about 560 TeV, the variation can be up to 20.1%. In an electric field of –1700 V·cm^–1（above the threshold of the RREA process）, the increasing amplitude of the lateral distribution is greater than that in an electric field of –1000 V·cm^–1. And the amplitude is 3.8% for θ=0° and 34% for θ=50°, respectively. For the primary energy of about 180 GeV, the increasing amplitude of secondary particles is 9.9%. For the primary energy of about 560 TeV, the variation can be as high as 119%. Our simulation results are helpful to understand the deflection mechanisms of cosmic ray secondary particles generated by the near-earth thunderstorms electric field, as well as the variation of LHAASO data during thunderstorms.更多还原