SUN-TO-EARTH CHARACTERISTICS OF THE 2012 JULY 12 CORONAL MASS EJECTION AND ASSOCIATED GEO-EFFECTIVENESS
SUN-TO-EARTH CHARACTERISTICS OF THE 2012 JULY 12 CORONAL MASS EJECTION AND ASSOCIATED GEO-EFFECTIVENESS
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DOI：
10.3847/0004-637x/829/2/97
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
Huidong Hu;Y. Liu;Rui Wang;C. Möstl;Zhongwei Yang
中科院分区：
文献类型：
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作者：
Huidong Hu;Y. Liu;Rui Wang;C. Möstl;Zhongwei Yang
我们分析了与2012年7月12日日冕物质抛射（CME）相关的多航天器观测，包括太阳动力学天文台的太阳源区域，日地关系天文台（STEREO）的立体成像观测，水星表面的磁场特征，空间环境，地球化学和测距（信使），和II型无线电爆发和现场测量风。一个三角测量方法的基础上STEREO立体观测的CME的运动学，并与来自II型射电爆发使用太阳风电子密度模型的结果进行了比较。一个梯度Shafranov技术应用于风在现场数据重建的通量绳结构，并将其与太阳源区的观测，这有助于了解与CME结构的地球有效性。我们的结论是：（1）CME在到达信使号之前经历了一个脉冲加速、快速减速和逐渐减速到1 Au的过程，这是CME运动学模型中应该考虑的;（2）II型射电爆发可能产生于CME驱动激波与附近流光的高密度相互作用区或激波侧面较低的高度，（3）在Wind上由现场重建得到的通量绳方向和手征与由太阳源观测得到的结果一致;（4）地球附近的长期南向磁场主要来自大幅度南倾的磁绳的轴向分量，这表明磁绳方向和磁场分量的预测在地磁活动预测中的重要性。
We analyze multi-spacecraft observations associated with the 2012 July 12 coronal mass ejection (CME), covering the source region on the Sun from the Solar Dynamics Observatory, stereoscopic imaging observations from the Solar Terrestrial Relations Observatory (STEREO), magnetic field characteristics from Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER), and type II radio burst and in situ measurements from Wind. A triangulation method based on STEREO stereoscopic observations is employed to determine the kinematics of the CME, and the outcome is compared with the results derived from the type II radio burst using a solar wind electron density model. A Grad–Shafranov technique is applied to Wind in situ data to reconstruct the flux-rope structure and compare it with the observations of the solar source region, which helps in understanding the geo-effectiveness associated with the CME structure. Our conclusions are as follows: (1) the CME undergoes an impulsive acceleration, a rapid deceleration before reaching MESSENGER, and then a gradual deceleration out to 1 au, which should be considered in CME kinematics models; (2) the type II radio burst was probably produced from a high-density interaction region between the CME-driven shock and a nearby streamer or from the shock flank with lower heights, which implies uncertainties in the determination of CME kinematics using solely type II radio bursts; (3) the flux-rope orientation and chirality deduced from in situ reconstructions at Wind agree with those obtained from solar source observations; (4) the prolonged southward magnetic field near the Earth is mainly from the axial component of the largely southward inclined flux rope, which indicates the importance of predicting both the flux-rope orientation and magnetic field components in geomagnetic activity forecasting.