耀斑活动区纵向磁场突变
Abrupt longitudinal magnetic field changes in flaring active regions
摘要：
本文用Gong的1分钟磁象图描述了38次X级和39次M级耀斑期间位于盘心$65^{\circ}$内的光球纵向磁场的变化。在所有77例中，我们确定至少有一个网站在耀斑活动区，明确的，永久的，逐步的字段发生变化。场变化的中位持续时间约为15分钟，X级和M级耀斑的场变化的中位持续时间大致相等。在两个例外情况下，场变化的绝对值范围从$\sim\!\!10$ ~G的检测限到高达$\sim\!\!450$ ~G。中位值为69~G。X级耀斑的磁场变化明显强于M级耀斑，肢体耀斑的磁场变化明显强于盘心耀斑。纵向磁场变化小于100~G时，无论是靠近盘中心还是靠近肢体，纵向磁场强度都有降低的趋势，而磁场变化大于100~G时，纵向磁场强度没有降低的趋势。同样地，在耀斑期间，纵向通量强度趋于减小。通量的变化，特别是净通量的变化，磁盘中心附近，相关性比当地的磁场变化与GOES峰值X射线通量。最强的纵向场和通量的变化发生在耀斑观察接近的肢体。我们估计了与每次耀斑相关的洛伦兹力的变化，并发现在某些情况下这足够大，可以为地震波提供动力。我们发现，纵向场的减少可能会超过增加在所有部分的太阳盘中心的$65^{\circ}$，在我们的观察，如果光球场倾斜增加耀斑期间预测的哈德森等人。
英文摘要：
We characterize the changes in the longitudinal photospheric magnetic field during 38 X-class and 39 M-class flares within $65^{\circ}$ of disk-center using 1-minute GONG magnetograms. In all 77 cases we identify at least one site in the flaring active region where clear, permanent, stepwise field changes occurred. The median duration of the field changes was about 15 minutes and was approximately equal for X-class and for M-class flares. The absolute values of the field changes ranged from the detection limit of $\sim\!\!10$~G to as high as $\sim\!\!450$~G in two exceptional cases. The median value was 69~G. Field changes were significantly stronger for X-class than for M-class flares and for limb flares than for disk-center flares. Longitudinal field changes less than 100~G tended to decrease longitudinal field strengths, both close to disk-center and close to the limb, while field changes greater than 100~G showed no such pattern. Likewise, longitudinal flux strengths tended to decrease during flares. Flux changes, particularly net flux changes near disk-center, correlated better than local field changes with GOES peak X-ray flux. The strongest longitudinal field and flux changes occurred in flares observed close to the limb. We estimate the change of Lorentz force associated with each flare and find that this is large enough in some cases to power seismic waves. We find that longitudinal field decreases would likely outnumber increases at all parts of the solar disk within $65^{\circ}$ of disk-center, as in our observations, if photospheric field tilts increase during flares as predicted by Hudson et al.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
