AN MHD MODEL FOR MAGNETAR GIANT FLARES
AN MHD MODEL FOR MAGNETAR GIANT FLARES
复制标题
磁巨耀斑的 MHD 模型
DOI：
10.1088/0004-637x/785/1/62
复制
发表时间：
2014-02
影响因子：
4.9
通讯作者：
Yuan F.
中科院分区：
文献类型：
--
作者：
Meng Y.;Lin J.;Zhang L.;Reeves K. K.;Zhang Q. S.;Yuan F.
软伽马射线中继器上的巨大耀斑被认为发生在磁星上，在很短的时间间隔内释放出巨大的能量。它们的威力可以用磁场构型和随后的磁重联中发生的灾难性不稳定性来解释。通过类比太阳上的日冕物质抛射事件，我们用解析方法建立了磁星巨型耀斑的理论模型。在该模型中，地壳的旋转和/或位移导致磁场扭曲和变形，导致磁层中磁绳的形成和相关构型中的能量积累。当储存在构型中的能量和螺旋度达到阈值时，系统失去平衡，磁绳以灾难性的方式向外喷射，磁重联帮助灾变发展到可能的喷发。以SGR1806−20为例，我们计算了这种爆发过程中释放的自由磁能，发现它大于1047erg，足以驱动一次巨型耀斑。释放的自由磁能被转化为磁绳的辐射能、动能和引力能。计算了SGR1806−20、SGR0526−66和SGR1900+14巨型耀斑爆发过程的光曲线，并与观测数据进行了比较。计算得到的光变曲线与观测到的巨型耀斑光变曲线吻合较好。
Giant flares on soft gamma-ray repeaters that are thought to take place on magnetars release enormous energy in a short time interval. Their power can be explained by catastrophic instabilities occurring in the magnetic field configuration and the subsequent magnetic reconnection. By analogy with the coronal mass ejection events on the Sun, we develop a theoretical model via an analytic approach for magnetar giant flares. In this model, the rotation and/or displacement of the crust causes the field to twist and deform, leading to flux rope formation in the magnetosphere and energy accumulation in the related configuration. When the energy and helicity stored in the configuration reach a threshold, the system loses its equilibrium, the flux rope is ejected outward in a catastrophic way, and magnetic reconnection helps the catastrophe develop to a plausible eruption. By taking SGR 1806−20 as an example, we calculate the free magnetic energy released in such an eruptive process and find that it is more than 1047 erg, which is enough to power a giant flare. The released free magnetic energy is converted into radiative energy, kinetic energy, and gravitational energy of the flux rope. We calculated the light curves of the eruptive processes for the giant flares of SGR 1806−20, SGR 0526−66, and SGR 1900+14, and compared them with the observational data. The calculated light curves are in good agreement with the observed light curves of giant flares.
登录
查看更多内容
影响因子：
64.8
作者：
K. Hurley;T. Cline;E. Mazets;S. Barthelmy;P. Butterworth;F. Marshall;D. Palmer;R. Aptekar'
通讯作者：
K. Hurley;T. Cline;E. Mazets;S. Barthelmy;P. Butterworth;F. Marshall;D. Palmer;R. Aptekar'
影响因子：
2
作者：
J. Lin;W. Soon
通讯作者：
J. Lin;W. Soon
影响因子：
64.8
作者：
E. Mazets;S. Golenetskii;V. Il’inskii;R. Aptekar';Yu. A. Guryan
通讯作者：
E. Mazets;S. Golenetskii;V. Il’inskii;R. Aptekar';Yu. A. Guryan
与日冕变暗相关的交感丝状喷发
影响因子：
4.9
作者：
Jiang, Yunchun;Yang, Jiayan;Hong, Junchao;Bi, Yi;Zheng, Ruisheng
通讯作者：
Zheng, Ruisheng
影响因子：
64.8
作者：
P. B. Cameron;P. Chandra;P. Chandra;A. Ray;S. Kulkarni;D. Frail;M. Wieringa;E. Nakar;E. Phinn
通讯作者：
P. B. Cameron;P. Chandra;P. Chandra;A. Ray;S. Kulkarni;D. Frail;M. Wieringa;E. Nakar;E. Phinn