Solar Cosmic Rays of February, 1956 and Their Propagation through Interplanetary Space
Solar Cosmic Rays of February, 1956 and Their Propagation through Interplanetary Space
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1956 年 2 月的太阳宇宙射线及其在行星际空间中的传播
DOI：
10.1103/physrev.104.768
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发表时间：
1956
期刊：
影响因子：
--
通讯作者：
J. Simpson
中科院分区：
文献类型：
--
作者：
P. Meyer;E. Parker;J. Simpson
分布在地磁纬度范围很广的六个中子强度监测器的数据已被用来研究1956年2月23日发生的与太阳耀斑有关的宇宙线强度的大而暂时的增加。在强度增强期间，球载中子探测器测量了高空耀斑粒子的吸收、平均自由程和强度。从这些实验的初级粒子强度谱作为粒子刚度的函数，在范围< 2 to>15-30 Bv的刚度，已推导出不同的时间在增强强度期间。结果表明，太阳和地球之间的区域应该没有大于10 - 6高斯的磁场，并且在最大耀斑粒子强度之后的16小时内，入射辐射几乎是各向同性的。粒子强度随时间t的衰减依赖于t− 3 2的幂律，除了高能粒子和晚期粒子，它们的时间依赖性接近指数。这些实验导致了一个内太阳系的模型，它需要一个半径大于日地距离的无场空腔，由不规则磁场[B（rms）<$10 − 5高斯]的连续屏障区包围，宇宙射线粒子必须通过该屏障区扩散才能到达星际空间。这个屏障也被用来将耀斑粒子散射回无场腔，并确定在地球上观测到的强度下降速率。时间依赖性t− 3 2代表了扩散方程在实验证据所要求的初始和边界条件下的特解，这一事实有力地支持了扩散机制。扩散系数，磁场区域的大小，势垒和空腔的尺寸，以及高能太阳注入粒子的总动能已被估计为这个模型。最近对行星际空间的研究表明，这些实验所提出的条件可能在太阳系中不时地建立起来。将该模型推广到解释早期的宇宙线耀斑观测似乎是令人满意的。
The data from six neutron-intensity monitors distributed over a wide range of geomagnetic latitudes have been used to study the large and temporary increase of cosmic-ray intensity which occurred on February 23, 1956, in association with a solar flare. During the period of enhanced intensity a balloon-borne neutron detector measured the absorption mean free path and intensity of the flare particles at high altitudes. From these experiments the primary particle intensity spectrum as a function of particle rigidity, over the range< 2 to> 15-30 Bv rigidity, has been deduced for different times during the period of enhanced intensity. It is shown that the region between the sun and the earth should be free of magnetic fields greater than∼ 10− 6 gauss and that the incoming radiation was practically isotropic for more than 16 hours following maximum flare particle intensity. The decline of particle intensity as a function of time t depends upon the power law t− 3 2, except for high-energy particles and late times, where the time dependence approaches an exponential. The experiments lead to a model for the inner solar system which requires a field-free cavity of radius greater than the sun-earth distance enclosed by a continuous barrier region of irregular magnetic fields [B (rms)≈ 10− 5 gauss] through which the cosmic-ray particles must diffuse to reach interstellar space. This barrier is also invoked to scatter flare particles back into the field-free cavity and to determine the rate of declining intensity observed at the earth. The diffusion mechanism is strongly supported by the fact that the time dependence t− 3 2 represents a special solution of the diffusion equation under initial and boundary conditions required by experimental evidence. The coefficient of diffusion, the magnitude of the magnetic field regions, the dimensions of the barrier and cavity, and the total kinetic energy of the high-energy solar injected particles have been estimated for this model. Recent studies of interplanetary space indicate that the conditions suggested by the experiments may be established from time to time in the solar system. The extension of the model to the explanation of earlier cosmic-ray flare observations appears to be satisfactory.