EFFECTS OF THE INTENSITY OF MAGNETIC FIELD ON THE STEADY CORONAL STRUCTURE
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摘要: 以二维MHD模型及时变方法为基础,内外边界采用完整的投影特征线边界条件,考察了太阳日冕大气的定态结构随偶极场强度的变化情况.模拟结果表明: 随着偶极场强度的增加,磁场对太阳风的约束增强,低纬闭磁场打开程度减小,高纬与低纬区速度差增加,并且在阿尔文马赫数为1的点附近达到最大,速度过度区变陡;随着日心距离增加,低纬区宽度减小,速度过渡区变陡,可定性解释Ulysses飞船的新观测事实.Abstract: Based on the 2-D MHD model and time relaxation method, using the pro- jective characteristic boundary conditions on the inner and outer boundaries, the effects of the magnetic field intensity on the steady coronal structures are investigated. The simulation results show that with the increasing dipolar magnetic field, the constraint of the magnetic field on the solar wind is strengthened, the degree of opening of the close magnetic field in the lower latitude decreases, the velocity difference between the higher latitude and the lower latitude increases, taking maximum near the point where Alfvenic mach number is 1, and the velocity transition region is steepened. On the other hand, with the increasing heliospheric distance, the velocity transition region is also steepened. The result can be used to qualitatively explain the Ulysses observations in the region far from the sun.
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Key words:
- Coronal /
- Magnetic field /
- Solar wind
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