论文标题
太阳周期降期的活动区域中的磁和速度场拓扑23
Magnetic and Velocity Field Topology in Active Regions of Descending Phase of the Solar Cycle 23
论文作者
论文摘要
我们分析了在太阳周期23的峰值到峰值降级阶段观察到的几个活性区域（AR）的光晶磁场和亚光层流的拓扑结构。我们的分析显示了所有磁性参数中半球偏好的明确证据，例如磁性，电流和动力学刺激性，以及“ Curl curl-diververvence”。我们发现北半球（阳性）磁性螺旋性的北半球为68 \％（67 \％）。在68 \％（68 \％）ARS中，发现当前的螺旋度相同的半球偏好符号。除了在太阳周期的峰和末端阶段观察到的少数AR之外，发现半球偏好在统计上一直存在于统计上。这意味着磁场在比北半球（南部）半球的单个AR小的尺度上主要留下（右）。我们发现磁性和当前的螺旋性参数显示出与黑子周期相似的赤道传播。动力学螺旋性显示出与磁性和当前螺旋性参数相似的半球趋势。在北部（南部）半球的深度为2.4 \，MM的深度为65 \％（56 \％）ARS，具有阴性（阳性）动力学螺旋性和散射螺旋。动力学螺旋度的半球分布在较大的深度上变得更加明显，例如，在12.6 \，mm的深度下为69 \％（67 \％）。动力学螺旋的类似半球趋势与当前的螺旋性支持平均场发电机模型。我们还发现，所有参数的半球分布随ARS的场强度增加。光球磁场和近表面亚光层流场的拓扑表现不佳，但它们之间的相关性与深度相关性增强了，这可能表明在ARS的深层层上更加对齐流。
We analyse the topology of photospheric magnetic fields and sub-photospheric flows of several active regions (ARs) that are observed during the peak to descending phase of the solar cycle 23. Our analysis shows clear evidence of hemispheric preferences in all the topological parameters such as the magnetic, current and kinetic helicities, and the 'curl-divergence'. We found that 68\%(67\%) ARs in the northern (southern) hemisphere with negative (positive) magnetic helicities. Same hemispheric preference sign is found for the current helicities in 68\%(68\%) ARs. The hemispheric preferences are found to exist statistically for all the time except in few ARs observed during the peak and the end phases of the solar cycle. This means that magnetic fields are dominantly left(right)-helical in scales smaller than individual ARs of northern(southern) hemisphere. We found that magnetic and current helicities parameters show equator-ward propagation similar to the sunspot cycle. The kinetic helicity showed similar hemispheric trend to that of magnetic and current helicity parameters. There are 65\%(56\%) ARs with negative (positive) kinetic helicity as well as divergence-curl, at the depth of 2.4\,Mm, in the northern (southern) hemisphere. The hemispheric distribution of the kinetic helicity becomes more evident at larger depths, e.g., 69\%(67\%) at the depth of 12.6\,Mm. Similar hemispheric trend of kinetic helicity to that of the current helicity supports the mean field dynamo model. We also found that the hemispheric distribution of all the parameters increases with the field strength of ARs. The topology of photospheric magnetic fields and near surface sub-photospheric flow fields did not show good association but the correlation between them enhances with depths which could be indicating more aligned flows at deeper layers of ARs.
