CROSS-FIELD TRANSPORT OF SOLAR ENERGETIC PARTICLES IN A LARGE-SCALE FLUCTUATING MAGNETIC FIELD
CROSS-FIELD TRANSPORT OF SOLAR ENERGETIC PARTICLES IN A LARGE-SCALE FLUCTUATING MAGNETIC FIELD
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DOI：
10.1088/0004-637x/750/1/47
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发表时间：
2012-02
期刊：
影响因子：
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通讯作者：
J. Kelly;Silvia Dalla;Timo Laitinen
中科院分区：
文献类型：
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作者：
J. Kelly;Silvia Dalla;Timo Laitinen
太阳高能粒子在行星际磁场中的轨迹表现出大规模的波动，由于起源于光球的足点运动模拟使用全轨道测试粒子代码。粒子在三种传播条件（无散射、散射平均自由程λ = 0.3 Au和λ = 2 Au）下经历的交叉场输运在帕克螺旋几何中被表征。在从模拟输出计算粒子位移和扩散系数时，考虑了磁场随太阳径向距离的膨胀的作用。结果表明，在λ = 0.3 Au和λ = 2 Au的情况下，与无散射的情况相比，在磁场中的输运增强.垂直扩散系数与平行扩散系数的比值在0.01和0.08之间变化。垂直于磁场的纬向与纵向扩散系数之比通常为0.2，这表明纬度上的传输效率可能较低。
The trajectories of solar energetic particles in an interplanetary magnetic field exhibiting large-scale fluctuations due to footpoint motions originating in the photosphere are simulated using a full-orbit test-particle code. The cross-field transport experienced by the particles in three propagation conditions (scatter-free, with scattering mean free path λ = 0.3 AU and λ = 2 AU) is characterized in the Parker spiral geometry. The role of expansion of the magnetic field with radial distance from the Sun is taken into consideration in the calculation of particle displacements and diffusion coefficients from the output of the simulations. It is found that transport across the magnetic field is enhanced in the λ = 0.3 AU and λ = 2 AU cases, compared to the scatter-free case. Values of the ratios of perpendicular to parallel diffusion coefficients vary between 0.01 and 0.08. The ratio of latitudinal to longitudinal diffusion coefficient perpendicular to the magnetic field is typically 0.2, suggesting that transport in latitude may be less efficient.