Line profile analysis of a coronal formation observed near a quiescent prominence: Intensities, temperatures and velocity fields
Line profile analysis of a coronal formation observed near a quiescent prominence: Intensities, temperatures and velocity fields
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在静止日珥附近观察到的日冕结构的线剖面分析：强度、温度和速度场
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发表时间：
1975
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通讯作者：
T. Tsubaki
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作者：
T. Tsubaki
本文介绍了一种快速、高精度的谱线分析技术，用于研究静止日珥附近日冕形成的物理条件。对五条日冕谱线（Fe xiv λ 5303、Fe x λ 6374、Ni xv λ 6702、Fe xv λ 7059和Fe xi λ 7892）的详细分析提供了总强度、多普勒宽度温度、电离温度和速度。绿色线的强度在观测到的静止日珥周围显示出一个局部极小值;在红色线的强度中可以看到一个相应的但更加弥散的图案。特别是，
$$ar T_D（λ 5303）= 3.2 10^6千美元
，而
$$ar T_e（xv/xIv）= 2.6 10^6 K， ar T_e（xIv/x）= 1.5 10^6千美元
得双曲正弦值.
$$ar T_e（xI/x）= 1.2 10^6千美元
.之间的差异
$$ar T_e（xv/xIv）$$
和
$$ar T_e（xI/x）$$
是温度不均匀性的直接证据。因此，人们可以在Te（xi/x）中赋予很小的意义。TD（λ5303）和Te（xv/xiv）在每个狭缝高度几乎平行波动，在日珥周围有一个弱的局部极小值。如果假设非热湍流运动为6-16 km s-1，则可以消除这两者之间的差异。TD（λ5303）和Te（xv/xiv）随高度的变化表明，日冕温度最高值位于距针状体顶部不超过15000 km处。TD（λ5303）的高度变化有一个约6 deg km−1的负梯度，绿色线波长的高度变化表明，这一区域的日冕物质在太阳表面是自西向东流动的，最低高度处的速度最高，为12 km s−1。这种运动与附近日冕雨的运动是相同的，这是由光谱和波长移动的Hα滤波图确定的。叠加在上述流动上的是一个高达±5 km s−1的系统速度场。这个磁场同样在最低高度达到最大振幅，在日珥周围出现局部极大值。
AbstractA technique developed for analysing line profiles with both speed and high accuracy was used to study the physical conditions of a coronal formation near a quiescent prominence. Detailed analyses of five coronal lines (Fe xiv λ 5303, Fe x λ 6374, Ni xv λ 6702, Fe xv λ 7059, and Fe xi λ 7892) provided total intensities, Doppler width temperatures, ionization temperatures, and velocities.Dissimilar spatial fluctuations in intensity are obvious for ions grouped according to (low vs high) ionization potentials. The intensity of the green line shows a local minimum around the observed quiescent prominence; a corresponding but much more diffuse pattern is visible in the red line intensity.Large differences are observed in temperatures derived by different means. In particular,
$$ar T_D (lambda 5303) = 3.2 imes 10^6 K$$
, while
$$ar T_e (xv/xIv) = 2.6 imes 10^6 K, ar T_e (xIv/x) = 1.5 imes 10^6 K$$
, and
$$ar T_e (xI/x) = 1.2 imes 10^6 K$$
. The differences between
$$ar T_e (xv/xIv)$$
and
$$ar T_e (xI/x)$$
are taken as direct evidence of temperature inhomogeneity. One can thus put little significance in Te (xi/x). TD(λ5303) and Te(xv/xiv) fluctuate nearly in parallel at each slit height, with a weak local minimum evident around the prominence. The discrepancy between these two can be removed if a non-thermal turbulent motion of 6–16 km s−1 is assumed. Variations with height of both TD(λ5303) and Te(xv/xiv) suggest that the coronal temperature maximum is located no more than 15000 km above the top of spicules. A negative gradient of about 6 deg km−1 is found in the height variation of TD(λ5303).The height variation of the green line wavelength shows that the majority of coronal material in this region is flowing from west to east on the Sun, with the highest velocity of 12 km s−1 found at the lowest heights. This motion is in the same sense as that of the nearby coronal rain, as determined both from the spectra and wavelength-shifted Hα filtergrams. Superposed on the above flow is a systematic velocity field of up to ±5 km s−1. This field similarly reaches maximum amplitudes at lowest heights showing a local maximum around the prominence.