Dipped Magnetic Field Configurations Associated with Filaments and Barbs
Dipped Magnetic Field Configurations Associated with Filaments and Barbs
复制标题
与细丝和倒刺相关的倾斜磁场配置
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发表时间：
1999
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影响因子：
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通讯作者：
E. Priest
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文献类型：
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作者：
D. Mackay;A. Longbottom;E. Priest
本文考虑了与细丝有关的三维线性无力场位形。假设如果灯丝包含磁倾角，则场构型适合表示灯丝。当光球通量分布被选为具有右旋/左旋轴分量的拱形时，发现只有在较大的α值(其中，∇×B=αB)时才存在倾斜构形。倾角始终位于磁通区之间通道中心的极性反转线上方。当从上方观察到1毫米的深度时，它们非常类似于在太阳圆盘上观察到的吸收的细丝的形状。随着阿尔法的大小增加，水平和垂直的凹陷范围也增加，对于低的阿尔法值，产生活跃的细丝，而对于高的阿尔法值，产生静默的细丝。右旋细丝仅在α为负值时形成，而左旋细丝仅在α为正值时形成。倾斜的场线部分总是反极性的，并且倾斜区域的场强随着高度的增加而增加，这两个结果都与Leroy，Bommier和Sahal-Béchot(1983)的结果一致。在倾角区域的上方有正常极性的拱形，这些拱形具有正确的左/右方向，即右旋/左旋细丝。当使用倾斜场线中出现倒钩的假设时，右旋/左旋细丝从主轴向右/向左分支的倒钩可以在极性反转线两侧的少数极性元素周围形成。正常的极性元素周围没有倒钩。该模型再现了许多观察到的细丝通道、细丝及其倒钩的特征。
In this paper, three-dimensional linear force-free field configurations that can be associated with filaments are considered. It is assumed that the field configurations are suitable to represent filaments if they contain magnetic dips. With the photospheric flux distribution chosen to be an arcade with a dextral/sinistral axial component, it is found that dipped configurations exist only for large values of alpha (where, ∇×B=αB). The dips always lie above the polarity inversion line in the centre of the channel between the flux regions. When the dips are viewed from above to a depth of 1 Mm they resemble closely the shape of filaments viewed in absorption on the solar disk. As the magnitude of alpha increases, the horizontal and vertical extent of the dips also increases, giving active-region filaments for low values of alpha and quiescient filaments for high values of alpha. Dextral filaments only form for negative values of alpha and sinistral filaments for positive values of alpha. The portion of the field line that is dipped is always of inverse polarity and the magnitude of the field in the dipped region increases with height, both of which are consistent with Leroy, Bommier, and Sahal-Bréchot (1983). Overlying the region of dips there are arcades of normal polarity which have the correct left-bearing/right-bearing orientation for dextral/sinistral filaments. When the hypothesis of barbs occurring in dipped field lines is used, barbs that branch out of the main axis and to the right/left for dextral/sinistral filaments can be formed around minority polarity elements on either side of the polarity inversion line. No barbs are found around normal polarity elements. The model reproduces many of the observed features of filament channels, filaments and their barbs.