Atmosphere Models of Coronal Hole Network
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摘要: 本文采用非径向磁流管位形的假设,计算了太阳冕洞网络部分的色球-日冕过渡区的能量平衡模型。所考虑的能量流包括辐射、传导、对流和机械波加热(如阿尔芬波),计算结果表明在冕洞网络部分的过渡区中,电子温度T和密度N分别比宁静太阳中的值低60%和2倍,而其过渡区的厚度比宁静太阳中的大4倍。这种大气模型可满意地解释T≥105K范围的远紫外观测发射量度的分布。另外我们也发现在冕洞大气的过渡区中,阿尔芬波加热似乎不能忽略,尤其是在冕洞的过渡区底部,它的加热作用可能会超过热传导。在冕洞大气中,由于波动量的淀积而产生的对流能损耗也是重要的,在过渡区底部650km以上,对流能损耗逐渐超过辐射损耗。Abstract: Energy balance models of the chromosphere-corona transition region are computed for a segment of coronal hole assuming a nonradial magnetic field geometry.The energy fluxes considered include radiation,conduction,convection and mechanical wave (e.g.Alfven waves) heating.The calculated results show that the temperature T is about 60% lower,the electron density N is twice smaller and the thickness of the transition region is four times larger in the coronal hole network than in those the quiet region.This atmosphere model can satisfactorily explain the emission measure distribution obtained from the EUV observations for T>105K.In addition it is also found that the Alfven wave heating at the base of the transition region of coronal hole may exceed the heat conduction.The convection energy losses could be important in coronal hole atmosphere due to the wave momentum deposition.In the transition region at the heights greater than 650 km above the base of the transition region the convection energy losses may gradually exceed the radiation energy losses.
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