ON THE CONSTANCY OF THE ELECTRON TEMPERATURE IN THE EXPANDING CORONA THROUGHOUT SOLAR CYCLE 23
ON THE CONSTANCY OF THE ELECTRON TEMPERATURE IN THE EXPANDING CORONA THROUGHOUT SOLAR CYCLE 23
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关于整个太阳周期中膨胀的日冕中电子温度的稳定性 23
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
A. Ding
中科院分区：
文献类型：
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作者：
S. Habbal;H. Morgan;M. Druckmüller;A. Ding
最近对2006年3月29日和2008年8月1日日全食期间观测到的Fe发射线的分析建立了膨胀日冕中的电子温度与行星际空间中测量的Fe电荷状态之间的第一个经验联系。在这封信中，我们使用这个链接来推断整个太阳活动周期23的温度，从太阳风离子成分光谱仪（SWICS）的高级成分探测器（ACE）和太阳能电池的原位电荷状态测量。从1998年到2009年，SWICS/ACE Fe电荷状态的分布是偏斜的，峰值集中在Fe 8+、Fe 9+和Fe 10+上，尾部跨越Fe 12+到Fe 20+。基于该分布和Fe离子分数作为电子温度的函数的迭代过程在1.1 × 106 K处产生窄峰。在测量的电荷态分布的尾部归因于零星释放的材料热超过2 × 106 K从封闭的磁结构内的凸起的流光。1992年至1997年期间，第22周期的Fe 11+电荷态测量在Fe 11+处达到峰值，表明温度略高，为1.5 × 106 K。在整个太阳活动周期23中，膨胀日冕中电子温度的相对恒定性表明，在这个周期中，在所有纬度的太阳风加速区域中，存在一种未知的机制，调节输入给电子的能量。
A recent analysis of Fe emission lines observed during the total solar eclipses of 2006 March 29 and 2008 August 1 established the first empirical link between the electron temperature in the expanding corona and Fe charge states measured in interplanetary space. In this Letter, we use this link to infer this temperature throughout solar cycle 23 from in situ charge state measurements from the Solar Wind Ion Composition Spectrometer (SWICS) on the Advanced Composition Explorer (ACE) and on Ulysses. The distribution of the SWICS/ACE Fe charge states, which span cycle 23 from 1998 to 2009, is skewed with a peak centered on Fe8+, Fe9+, and Fe10+ and a tail spanning Fe12+ to Fe20+. An iterative process based on this distribution and on the Fe ion fraction as a function of electron temperature yields a narrow peak at 1.1 × 106 K. The tail in the measured charge state distribution is attributed to the sporadic release of material hotter than 2 × 106 K from closed magnetic structures within the bulges of streamers. The Fe Ulysses charge state measurements between 1992 and 1997 from cycle 22 peaked at Fe11+, indicative of a slightly higher temperature of 1.5 × 106 K. The relative constancy of the electron temperature in the expanding corona throughout solar cycle 23 points to the presence of an unknown mechanism regulating the energy input to electrons in the acceleration region of the solar wind at all latitudes during this cycle.