基于太阳爆发灾变模型的数值实验
发布时间：2019-05-10 05:06
【摘要】：我们在Isenberg等人1993年发展的灾变模型的基础上,在接近真实的日冕环境的条件下,通过数值实验,对磁通量绳的平衡高度对背景磁场变化的响应开展了研究,利用NIRVANA程序进行了计算。我们的工作中的日冕等离子密度分布采用了一个半经验的模型,模拟中包含了物理耗散。我们考察了磁通量绳的平衡位置及其演化特征,参考半径的变化对磁通量绳平衡位置的影响,磁通量绳内部平衡的性质以及在磁通量绳失去平衡之后一段时间内的的动力学与运动学特征。结果表明:数值实验中得到的磁通量绳的平衡态位置与Isenberg等人的理论结果有一点微小的偏离,但是演化特征基本一致,在临界点处系统迅速失去平衡,向爆发态演化;参考半径的变化对磁通量绳平衡位置的影响与灾变模型给出的结果基本一致;磁通量绳在随着宏观磁结构演化的同时,还通过自身的调节达到内部平衡,当磁通量绳的内部和外部平衡都实现之后,系统整体也就达到了平衡状态;在爆发态下,磁通量绳的运动特征与Lin-Forbes模型和观测给出的结果一致,并且在通量绳的前沿有快模激波出现;由于数值实验中包括了耗散,爆发过程中的磁能向其它形式的能量的转换非常明显。
[Abstract]:On the basis of the catastrophe model developed by Isenberg et al in 1993, and under the condition of approaching the real coronal environment, the response of the equilibrium height of magnetic flux rope to the change of background magnetic field is studied by numerical experiments. The calculation is carried out by NIRVANA program. A semi-empirical model is used for the distribution of coronal plasma density in our work, and physical dissipation is included in the simulation. We investigate the equilibrium position and evolution characteristics of the magnetic flux rope, and the influence of the change of the reference radius on the equilibrium position of the magnetic flux rope. The properties of the internal equilibrium of the magnetic flux rope and the dynamic and kinematic characteristics of the magnetic flux rope in the period after the loss of the balance of the magnetic flux rope. The results show that the equilibrium position of the magnetic flux rope obtained in the numerical experiment deviates slightly from the theoretical results of Isenberg et al., but the evolution characteristics are basically the same. The system loses its equilibrium rapidly at the critical point and evolves to the explosive state. The influence of the change of reference radius on the equilibrium position of magnetic flux rope is basically consistent with the results given by the catastrophe model. With the evolution of the macro magnetic structure, the magnetic flux rope also achieves the internal balance through its own adjustment. When the internal and external balance of the magnetic flux rope is realized, the system as a whole reaches the equilibrium state. In the explosive state, the motion characteristics of the magnetic flux rope are consistent with the Lin-Forbes model and the observed results, and there are fast mode shock waves at the front of the flux rope. Because dissipation is included in the numerical experiment, the conversion from magnetic energy to other forms of energy in the process of explosion is very obvious.
【学位授予单位】：中国科学院大学(中国科学院云南天文台)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P182
本文编号：2473367
[Abstract]:On the basis of the catastrophe model developed by Isenberg et al in 1993, and under the condition of approaching the real coronal environment, the response of the equilibrium height of magnetic flux rope to the change of background magnetic field is studied by numerical experiments. The calculation is carried out by NIRVANA program. A semi-empirical model is used for the distribution of coronal plasma density in our work, and physical dissipation is included in the simulation. We investigate the equilibrium position and evolution characteristics of the magnetic flux rope, and the influence of the change of the reference radius on the equilibrium position of the magnetic flux rope. The properties of the internal equilibrium of the magnetic flux rope and the dynamic and kinematic characteristics of the magnetic flux rope in the period after the loss of the balance of the magnetic flux rope. The results show that the equilibrium position of the magnetic flux rope obtained in the numerical experiment deviates slightly from the theoretical results of Isenberg et al., but the evolution characteristics are basically the same. The system loses its equilibrium rapidly at the critical point and evolves to the explosive state. The influence of the change of reference radius on the equilibrium position of magnetic flux rope is basically consistent with the results given by the catastrophe model. With the evolution of the macro magnetic structure, the magnetic flux rope also achieves the internal balance through its own adjustment. When the internal and external balance of the magnetic flux rope is realized, the system as a whole reaches the equilibrium state. In the explosive state, the motion characteristics of the magnetic flux rope are consistent with the Lin-Forbes model and the observed results, and there are fast mode shock waves at the front of the flux rope. Because dissipation is included in the numerical experiment, the conversion from magnetic energy to other forms of energy in the process of explosion is very obvious.
【学位授予单位】：中国科学院大学(中国科学院云南天文台)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P182
【参考文献】
相关期刊论文 前1条
1 ;Energetics and Propagation of Coronal Mass Ejections in Different Plasma Environments[J];Chinese Journal of Astronomy and Astrophysics;2002年06期
，本文编号：2473367
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