标题： 日冕物质抛射响应中的当前螺度 显示英文标题

标题： Current Helicity in Response to Coronal Mass Ejections

摘要： 日冕物质抛射（CMEs）是由日冕电流中储存的磁自由能释放引起的强大太阳喷发，将大量等离子体喷射到星际空间。光球电流螺旋度，定义为垂直电流密度和垂直磁场乘积的积分（$H_c=\int j_zB_z\ dS$），是理解喷发的关键参数。使用三维磁流体动力学模型，我们识别出与喷发相关的电流螺旋度反转模式：喷发前减少，喷发后增加。这种螺旋度反转归因于电流的重新分布：喷发前，电流集中在极性反转线（PIL）附近；喷发后，电流远离PIL，这与由向上进展的重联区域引起的耀斑条带分离一致。为了验证这一模式，我们对50个$\geq$M5.0 喷发耀斑进行了观测分析。结果表明，58%的案例在喷发前出现了减少，92%的案例在喷发后出现了增加。对两个具有这种反转的案例的详细分析表明，它们具有相同的电流重新分布模式，与模拟中确定的机制一致。此外，在这两个案例的长期演化中也可以清楚地观察到喷发前的减少。电流螺旋度可以作为指示电流传导用于后续喷发的指标，并且在一定程度上具有预测CMEs的潜力。 显示英文摘要

摘要： Coronal mass ejections (CMEs), powerful solar eruptions with massive plasma ejected into the interplanetary space, are caused by the release of the magnetic free enengy stored in coronal electric currents. Photospheric current helicity, defined as the integral of the product of vertical electric current density and vertical magnetic field ($H_c=\int j_zB_z\ dS$), serves as a key parameter in understanding the eruptions. Using a 3D magnetohydrodynamic model, we identify a current helicity reversal pattern associated with the eruption: a pre-eruption decrease and a post-eruption increase. This helicity reversal is attributed to the redistribution of electric currents: before the eruption, currents concentrate toward the polarity inversion line (PIL); after the eruption they move away from the PIL, consistent with the flare ribbon separation, which is caused by the upward progression reconnection site. To validate this pattern, we conducted an observational analysis of 50 $\geq$M5.0 eruptive flares. The results reveal that 58\% of cases exhibited a pre-eruption decrease and 92\% showed the post-eruption increase in current helicity. Detailed analysis of two cases with this reversal suggests that they share the same current redistribution pattern, consistent with the mechanism identified in the simulations. Moreover, the pre-eruption decrease could be observed clearly even in the long-term evolution of the two cases. Current helicity can serve as an indicator of when electric currents are built up for the subsequent eruption, and it has the potential to predict CMEs to some extent.