A RECONNECTION-DRIVEN RAREFACTION WAVE MODEL FOR CORONAL OUTFLOWS
A RECONNECTION-DRIVEN RAREFACTION WAVE MODEL FOR CORONAL OUTFLOWS
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DOI：
10.1088/0004-637x/743/1/66
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发表时间：
2011-12-10
影响因子：
4.9
通讯作者：
Del Zanna, G.
中科院分区：
文献类型：
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作者：
Bradshaw, S. J.;Aulanier, G.;Del Zanna, G.
我们进行数值实验，以确定是否在高海拔日冕零点的交换重联可以解释观测到的外流在开放和封闭的磁场区域之间的边界处的日冕发射线的蓝移。在这种情况下，一个强大的，重新连接后的压力梯度，形成在场对齐的方向时，密集和热，活跃的区域核心回路重新连接与邻近的脆弱和冷，开放的场线。我们发现，压力梯度驱动的超音速外流和稀疏波的发展在开放和封闭的后重联磁场区域。我们前向模型的光谱线轮廓的选择日冕发射线预测的光谱签名的稀疏波。我们发现，稀疏波的属性是一致的，所观察到的速度与温度结构的电晕在流出区域，其中的速度增加与发射线的形成温度。特别是，我们发现预测和观察到的Fe XII 195.119埃谱线轮廓之间的蓝移（10公里秒（-1）），半峰全宽（83米埃）和对称性极好的协议。最后，我们发现在开放场区域，T-i < T-e，这表明交换重联方案可能为慢太阳风提供一个可行的机制和源区。
We conduct numerical experiments to determine whether interchange reconnection at high altitude coronal null points can explain the outflows observed as blueshifts in coronal emission lines at the boundaries between open and closed magnetic field regions. In this scenario, a strong, post-reconnection pressure gradient forms in the field-aligned direction when dense and hot, active region core loops reconnect with neighboring tenuous and cool, open field lines. We find that the pressure gradient drives a supersonic outflow and a rarefaction wave develops in both the open and closed post-reconnection magnetic field regions. We forward-model the spectral line profiles for a selection of coronal emission lines to predict the spectral signatures of the rarefaction wave. We find that the properties of the rarefaction wave are consistent with the observed velocity versus temperature structure of the corona in the outflow regions, where the velocity increases with the formation temperature of the emission lines. In particular, we find excellent agreement between the predicted and observed Fe XII 195.119 angstrom spectral line profiles in terms of the blueshift (10 km s(-1)), full width at half-maximum (83 m angstrom) and symmetry. Finally, we find that T-i < T-e in the open field region, which indicates that the interchange reconnection scenario may provide a viable mechanism and source region for the slow solar wind.