EFFECTS OF LATITUDINALLY DEPENDENT SOLAR WIND SPEED ON DIFFUSION COEFFICIENTS OF COSMIC RAYS IN THE PRESENCE OF ADIABATIC FOCUSING
EFFECTS OF LATITUDINALLY DEPENDENT SOLAR WIND SPEED ON DIFFUSION COEFFICIENTS OF COSMIC RAYS IN THE PRESENCE OF ADIABATIC FOCUSING
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DOI：
10.1088/0004-637x/800/2/117
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发表时间：
2015-02
期刊：
影响因子：
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通讯作者：
H.-Q. He;R. Schlickeiser
中科院分区：
文献类型：
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作者：
H.-Q. He;R. Schlickeiser
观测到太阳风在高日纬度冕洞中表现为高速，而在黄道面附近表现为低速。与太阳风相关的日球磁场对带电高能粒子（包括银河宇宙线和太阳高能粒子）在三维日球中的传输和调制起着非常重要的作用。在以前的研究中，假设太阳风速恒定，与日纬度无关，并且通常用于宇宙线的调制建模。在这项工作中，我们调查的现实纬度依赖的太阳风的速度，并利用双曲线和分段多项式形式的理论模型，探讨在绝热聚焦的存在下，对日光层磁场和宇宙线的扩散系数（平行，垂直，和漂移尺度）的重要影响。比较了标准帕克场和修正磁场的扩散系数。由于不同的太阳风源（冕流带、极冕洞以及它们之间的过渡区）的结构和性质有本质的不同，我们建议在全球模拟日球层GCR和SEP的研究中，应采用与纬度相关的太阳风速度和相应的日球层磁场和绝热聚焦扩散系数。
The solar wind is observed to display high speeds in high heliolatitude coronal holes and low speeds near the ecliptic plane. The heliospheric magnetic field associated with the solar wind plays a very important role in the transport and modulation of charged energetic particles, including galactic cosmic rays (GCRs) and solar energetic particles (SEPs), in the three-dimensional heliosphere. In previous studies, a constant solar wind speed, which is independent of heliolatitude, was assumed and commonly used in modulation modeling of cosmic rays. In this work, we investigate the realistic latitudinally dependent solar wind speed and utilize the theoretical models in hyperbolic and piecewise polynomial forms to explore the important effects on the heliospheric magnetic field and the diffusion coefficients (parallel, perpendicular, and drift scale) of cosmic rays in the presence of adiabatic focusing. Comparisons of the diffusion coefficients derived from standard Parker field and modified magnetic fields are presented. Since the structures and properties of different solar wind sources (coronal streamer belt, polar coronal hole, and transition region between them) differ from each other in essence, we suggest that the latitudinally dependent solar wind speed and the corresponding heliospheric magnetic field and diffusion coefficients with adiabatic focusing should be employed in the global modeling studies of GCRs and SEPs in the heliosphere.