论文标题
“ ICME-In-In-insheath”现象的特征和重要性和地磁风暴活动的上限
Characteristics and Importance of "ICME-in-Sheath" Phenomenon and Upper Limit for Geomagnetic Storm Activity
论文作者
论文摘要
作为大型地磁风暴的重要来源，“ ICME In-In-sheath”是一个完全令人震惊的星际冠状质量射血（ICME），卡在冲击和宿主喷射之间的鞘中。从协调的多集观测值中确定了典型的特征：（1）通常持续时间短，在1 Au时持续几个小时； （2）它的太阳风参数，尤其是磁场，似乎在较大的距离方面保持增强； （3）常见的ICME签名通常会丢失。主机喷射可以是单个ICME或复杂的喷射，足够快以驱动冲击。这些结果阐明了对这种现象作为护套区域的正常部分的误解。在2012年7月23日的情况下，“ ICME-In-In-Insheath”现象以及预处理的效果以及在2012年7月23日的Case附近产生了一组极端的磁场，速度和密度。这可能是最极端的太阳风驱动，使我们能够估计地磁风暴活动的合理上限。通过在南部田地进行适当的修改，我们建议一场大约$ -2000 $ nt的$ d _ {\ rm st} $的地磁风暴原则上可能发生。从地球中心，地球同步轨道内部，磁胶将被压缩到约3.3地球半径。
As an important source for large geomagnetic storms, an "ICME-in-sheath" is a completely shocked interplanetary coronal mass ejection (ICME) stuck in the sheath between a shock and host ejecta. Typical characteristics are identified from coordinated multi-sets of observations: (1) it is usually short in duration and lasts a few hours at 1 AU; (2) its solar wind parameters, in particular the magnetic field, seem to keep enhanced for a large range of distances; and (3) common ICME signatures are often lost. The host ejecta could be a single ICME or a complex ejecta, being fast enough to drive a shock. These results clarify previous misinterpretations of this phenomenon as a normal part of a sheath region. The "ICME-in-sheath" phenomenon, together with a preconditioning effect, produced an extreme set of the magnetic field, speed and density near 1 AU in the 2012 July 23 case, all around their upper limits at the same time. This is probably the most extreme solar wind driving at 1 AU and enables us to estimate the plausible upper limit for geomagnetic storm activity. With an appropriate modification in the southward field, we suggest that a geomagnetic storm with a minimum $D_{\rm st}$ of about $-2000$ nT could occur in principle. The magnetopause would be compressed to about 3.3 Earth radii from the Earth's center, well inside the geosynchronous orbit.
