标题： 来自浮现太阳活动区的喷流事件的磁螺旋性和能量预算 显示英文标题

标题： Magnetic helicity and energy budgets of jet events from an emerging solar active region

摘要： 利用太阳动力学观测台（SDO）上的日震和磁成像仪获得的光球矢量磁图，以及基于磁场连接性的方法，我们计算了一个简单的双极太阳活动区（AR）在其磁场浮现阶段（持续了$\sim$47 小时）的磁螺旋性和自由磁场能量预算。该活动区在这一阶段没有引发任何日冕物质抛射（CMEs）或超过C1.0级的X射线耀斑，但在其磁场浮现期间发生了60次喷流事件。在整个研究的时间间隔内，该活动区的螺旋性和自由能量预算均低于已知与爆发相关的阈值。然而，除了缓慢变化的趋势外，螺旋性和自由能量预算的时间曲线还显示出离散的局部峰值，其中八次峰值分别发生在从该活动区发射出喷流的时候。这些喷流具有比活动区其他喷流更大的基底面积和更长的持续时间。我们首次估计了这八次喷流所关联的螺旋性和自由磁场能量的变化范围分别为$0.5-7.1 \times 10^{40}$Mx$^2$和$1.1-6.9 \times 10^{29}$erg。尽管这些数值比通常与CMEs相关联的值小一个到两个数量级，但归一化后的螺旋性百分比变化显著，范围在13%到76%之间；归一化后的自由磁场能量百分比变化范围在9%到57%之间。我们的研究表明，偶尔喷流可能在新兴活动区的螺旋性和自由磁场能量预算演化过程中留下显著印记。 显示英文摘要

摘要： Using photospheric vector magnetograms obtained by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory and a magnetic connectivity-based method, we compute the magnetic helicity and free magnetic energy budgets of a simple bipolar solar active region (AR) during its magnetic flux emergence phase which lasted $\sim$47 hrs. The AR did not produce any coronal mass ejections (CMEs) or flares with an X-ray class above C1.0 but it was the site of 60 jet events during its flux emergence phase. The helicity and free energy budgets of the AR were below established eruption-related thresholds throughout the interval we studied. However, in addition to their slowly-varying evolution, each of the time profiles of the helicity and free energy budgets showed discrete localized peaks, with eight pairs of them occurring at times of jets emanating from the AR. These jets featured larger base areas and longer durations than the other jets of the AR. We estimated, for the first time, the helicity and free magnetic energy changes associated with these eight jets which were in the ranges of $0.5-7.1 \times 10^{40}$ Mx$^2$ and $1.1-6.9 \times 10^{29}$ erg, respectively. Although these values are one to two orders of magnitude smaller than those usually associated with CMEs, the relevant percentage changes were significant and ranged from 13% to 76% for the normalized helicity and from 9% to 57% for the normalized free magnetic energy. Our study indicates that occasionally jets may have a significant imprint in the evolution of helicity and free magnetic energy budgets of emerging active regions.