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arXiv 2212.13397astro-ph.SRastro-ph.HEphysics.space-ph
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太阳磁场反转期间宇宙射线漂移效应的展开

Unfolding Drift Effects for Cosmic Rays over the Period of the Sun's Magnetic Field Reversal

O. P. M. Aslam, Xi Luo, M. S. Potgieter, M. D. Ngobeni, Xiaojian Song

AI总结:

利用三维宇宙射线调制模型模拟第24太阳周磁极反转前后的质子、电子、正电子及反质子,结合AMS观测揭示漂移减弱与恢复及平均自由程演化。

摘要:

本文采用一个成熟完善的综合三维数值调制模型,模拟2011年5月至2015年5月期间的银河质子、电子和正电子,涵盖第24太阳活动周的太阳磁极反转。研究目标是评估这些模拟结果与1.0–3.0 GV刚度范围内相应AMS观测结果的吻合程度,并从比较中揭示其背后的物理机制,从而增进对主要物理调制过程(尤其是粒子漂移)如何从负极性磁周期向正极性磁周期转变的理解。除局域星际谱不同外,电子与正电子仅在漂移模式上存在差异;而它们与质子还在其他方面不同,例如低刚度下的绝热能量变化。为完成对相反电荷粒子的模拟,研究还获得了反质子的建模结果。观测与相应模型共同揭示了近期磁极反转前后漂移模式的差异,并在很大程度上阐明了这一时期的电荷符号依赖现象。在这一没有明确磁极性的时期,全球粒子漂移效应变得可以忽略。磁极反转期间所有粒子的平均自由程(MFP)均处于较低值,与太阳活动极小期的较大值形成对比,由此揭示了从太阳活动极小期到极大期不同调制过程的相对贡献和影响。研究发现,漂移尺度在磁极反转后随即开始恢复,但平均自由程在反转后的一段时间内持续减小或保持不变。

英文摘要:

A well-established, comprehensive 3-D numerical modulation model is applied to simulate galactic protons, electrons and positrons from May 2011 to May 2015, including the solar magnetic polarity reversal of Solar Cycle 24. The objective is to evaluate how these simulations compare with corresponding AMS observations for 1.0-3.0 GV, and what underlying physics follows from this comparison in order to improve our understanding on how the major physical modulation processes change, especially particle drift, from a negative to a positive magnetic polarity cycle. Apart from their local interstellar spectra, electrons and positrons differ only in their drift patterns, but they differ with protons in other ways such as their adiabatic energy changes at lower rigidity. In order to complete the simulations for oppositely charged particles, antiproton modeling results are obtained as well. Together, the observations and the corresponding modeling indicate the difference in the drift pattern before and after the recent polarity reversal and clarify to a large extent the phenomenon of charge-sign dependence during this period. The effect of global particle drift became negligible during this period of no well-defined magnetic polarity. The resulting low values of all particles' MFPs during the polarity reversal contrast their large values during solar minimum activity, and as such expose the relative contributions and effects of the different modulation processes from solar minimum to maximum activity. We find that the drift scale starts recovering just after the polarity reversal, but the MFPs keep decreasing or remain unchanged for some period after the polarity reversal.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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