POSSIBLE EVIDENCE FOR A FISK-TYPE HELIOSPHERIC MAGNETIC FIELD. I. ANALYZING ULYSSES/KET ELECTRON OBSERVATIONS
POSSIBLE EVIDENCE FOR A FISK-TYPE HELIOSPHERIC MAGNETIC FIELD. I. ANALYZING ULYSSES/KET ELECTRON OBSERVATIONS
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DOI：
10.1088/0004-637x/741/1/23
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发表时间：
2011-11
期刊：
影响因子：
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通讯作者：
O. Sternal;N. E. Engelbrecht;R. A. Burger;S. Ferreira;H. Fichtner;B. Heber;A. Kopp;M. Potgieter;K. Scherer
中科院分区：
文献类型：
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作者：
O. Sternal;N. E. Engelbrecht;R. A. Burger;S. Ferreira;H. Fichtner;B. Heber;A. Kopp;M. Potgieter;K. Scherer
高能带电粒子在日球磁场中的传播是太阳物理学的基本问题之一。特别是，日光层磁场的结构仍然是一个未解决的问题，并作为一个有争议的话题进行讨论。第一个成功分析日球磁场结构的方法是帕克场。然而，在高纬度地区对近地天体航天器的测量表明，在太阳活动极小期可能需要改进现有的磁场模型。除其他原因外，这导致了菲斯克油田的发展。这种方法备受争议，迄今为止无法通过磁场测量排除。跟踪这种磁场结构的一种有前途的方法是在几兆电子伏的能量范围内模拟电子的传播。采用三维和随时间变化的模拟的高能电子的传播，这项工作表明，在日光层中的粒子传输的Fisk型场的影响导致的特征变化的电子强度的时间尺度上的太阳旋转。首次表明2.5-7 MeV电子的电子计数率包含Fisk型日球磁场结构的印记。从模拟结果和计数率的比较，现实的参数为菲斯克理论推导。此外，这些参数被用来调查建模的质子和电子的相对振幅，包括漂移的影响。
The propagation of energetic charged particles in the heliospheric magnetic field is one of the fundamental problems in heliophysics. In particular, the structure of the heliospheric magnetic field remains an unsolved problem and is discussed as a controversial topic. The first successful analytic approach to the structure of the heliospheric magnetic field was the Parker field. However, the measurements of the Ulysses spacecraft at high latitudes revealed the possible need for refinements of the existing magnetic field model during solar minimum. Among other reasons, this led to the development of the Fisk field. This approach is highly debated and could not be ruled out with magnetic field measurements so far. A promising method to trace this magnetic field structure is to model the propagation of electrons in the energy range of a few MeV. Employing three-dimensional and time-dependent simulations of the propagation of energetic electrons, this work shows that the influence of a Fisk-type field on the particle transport in the heliosphere leads to characteristic variations of the electron intensities on the timescale of a solar rotation. For the first time it is shown that the Ulysses count rates of 2.5–7 MeV electrons contain the imprint of a Fisk-type heliospheric magnetic field structure. From a comparison of simulation results and the Ulysses count rates, realistic parameters for the Fisk theory are derived. Furthermore, these parameters are used to investigate the modeled relative amplitudes of protons and electrons, including the effects of drifts.