O'Brien K, Sauer H H
Northern Arizona University, Flagstaff, AZ 86011-6010, USA. keran.o'
Adv Space Res. 2003;32(1):73-80. doi: 10.1016/s0273-1177(03)90373-5.
High-energy solar particles, produced in association with solar flares and coronal mass ejections, occasionally bombard the earth's atmosphere. resulting in radiation intensities additional to the background cosmic radiation. Access of these particles to the earth's vicinity during times of geomagnetic disturbances are not adequately described by using static geomagnetic field models. These solar fluxes are also often distributed non uniformly in space, so that fluxes measured by satellites obtained at great distances from the earth and which sample large volumes of space around the earth cannot be used to predict fluxes locally at the earth's surface. We present here a method which uses the ground-level neutron monitor counting rates as adjoint sources of the flux in the atmosphere immediately above them to obtain solar-particle effective dose rates as a function of position over the earth's surface. We have applied this approach to the large September 29-30, 1989 ground-level event (designated GLE 42) to obtain the magnitude and distribution of the solar-particle effective dose rate from an atypically large event. The results of these calculations clearly show the effect of the softer particle spectra associated with solar particle events, as compared with galactic cosmic rays, results in a greater sensitivity to the geomagnetic field, and, unlike cosmic rays, the near-absence of a "knee" near 60 degrees geomagnetic latitude.
与太阳耀斑和日冕物质抛射相关产生的高能太阳粒子偶尔会轰击地球大气层，导致辐射强度高于背景宇宙辐射。在地磁扰动期间，使用静态地磁场模型无法充分描述这些粒子进入地球附近的情况。这些太阳粒子通量在空间上也常常分布不均，因此，在远离地球且对地球周围大片空间进行采样的卫星所测得的通量，无法用于预测地球表面局部的通量。我们在此提出一种方法，该方法将地面中子监测器的计数率用作其上方紧邻大气层中通量的伴随源，以获取作为地球表面位置函数的太阳粒子有效剂量率。我们已将此方法应用于1989年9月29日至30日的大型地面事件（指定为GLE 42），以获取一次异常大型事件的太阳粒子有效剂量率的大小和分布情况。这些计算结果清楚地表明，与银河宇宙射线相比，与太阳粒子事件相关的较软粒子能谱的影响，导致对地球磁场的敏感性更高，并且与宇宙射线不同，在地磁纬度60度附近几乎不存在“拐点”。
