1 AU轨道SEP粒子通量的计算及与多卫星观测结果的比较

Calculation of the SEP Flux at 1 AU Orbit and Its Comparison with Multi-satellites Observations

1 AU轨道上太阳高能粒子(Solar EnergeticParticles,SEP)通量是空间天气的重要指标.将SEP两步传播方程的格林函数解进行数值化,模拟了2012年9月28日的SEP事件,首次计算了同一事件中GOES卫星与STEREO双星观测到的SEP通量变化过程.对GOES和STEREO-B观测点,计算所得SEP峰值I_(max)和峰值到达时间t_(max)与观测值符合较好;对STEREO-A,由于观测点与太阳活动源区间隔较大及太阳背面未知事件的影响,计算结果与观测存在一定差异.

The SEP （Solar Energetic Particles） flux at 1 AU orbit is an important index of space weather condition. Based on the parameterized Green Function solution of the SEP transport equa- tion in the ecliptic plane, the flux profile of the SEP event on 28 Sept. 2012 at GOES, STEREO-A and STEREO-B positions on the 1 AU orbit is calculated, and results are compared with available observations. The results show that the flux peak Ima~ and its occurrence time t of the SEP profile are well consistent with the observation of GOES and STEREO-B. However, for STEREO-A, there is an evident difference between our calculation and the observation, which may be induced by the large angle distance between the site and the SEP source and the unknown solar activities on the backside of the Sun. The parameterized SEP flux formula may be applicable for single source impulsive SEP events.