太阳爆发理论和模型在高能天体物理研究中的应用
发布时间：2019-04-24 08:45
【摘要】：日冕物质抛射是太阳表面的一种爆发现象,它可以使磁通量绳和磁化等离子体快速地抛射到外层日冕。在这个过程中巨大的磁场能量迅速释放,并转化为其他形式的能量。人们通常认为它的驱动机制主要为磁结构的灾变和磁重联。由于太阳是离地球最近的,而且是对人类最重要的一颗恒星,太阳物理,特别是对人类生活有重要影响的太阳爆发活动的研究得到了深入的发展。 在高能天体物理领域中,也存在着与日冕物质抛射相类似的物理现象。例如,磁中子星的大耀发以及黑洞吸积盘系统产生的间歇性喷流等,这些都是系统在短时间内释放大量的磁能并抛射物质的过程,而这些过程的具体细节还不被人们所知。因此,运用太阳爆发的相应理论和模型来对这些未知的活动进行研究,具有重要的借鉴作用。 软伽马射线复现源被认为是磁中子星的一种,发生在软伽马射线复现源中的大耀发在短时标内释放出巨大的能量。驱动这些爆发的能量来源与于贮存在磁中子星磁球层内的磁场能量,而触发和驱动机制则为磁场结构的灾变不稳定性和磁重联。参考太阳日冕物质抛射的理论和模型,我们发展了一个解析的理论模型来解释磁中子星的大耀发。在这个模型中,壳层的转动和错位造成磁场的扭曲和变形,导致磁通量绳在磁球层中形成以及能量在相应的磁场位形中积累。当储存在磁场结构中的能量和螺度达到了阈值,系统就会失去平衡,磁通量绳被以灾变的方式向外抛射,而磁重联使灾变演化成真正的爆发。以SGR1806-20为例,我们计算了在这样一次爆发过程中所释放出的磁自由能(即系统的总磁能和相应势场能量之差)大于1047尔格,足以驱动一次大耀发。释放的磁自由能被转化为辐射能、磁通量绳的动能和引力势能。我们还计算了SGR1806-20、SGR0526-66和SGR1900+14这三次大耀发过程的光变曲线并将他们与观测数据相比较。我们计算得出的光变曲线能很好地与观测数据符合。 在许多天体物理中的黑洞吸积盘系统中,由等离子体团构成的间歇性喷流已经被观测到,但是他们的起源还不清楚。以Yuan等人的模型为基础,我们发展了一个考虑了相对论效应的磁流体动力学模型来解释黑洞吸积盘系统中的间歇性喷流。我们以SgrA*和恒星级黑洞为例子,研究等间歇性喷流离子体团的动力学特征。我们的模型结果表明,等离子体团被抛射出去后,可以在短时间内获得很大的洛仑兹因子,并且不断地发生膨胀。然后,我们进一步地研究了相继抛射的等离子体团间的碰撞,发现恒星级黑洞产生的等离子体团之间可以发生碰撞,而单个等离子体团所携带的磁能大于1050尔格。在两个等离子体团的相互碰撞过程中,通过磁重联可将大约一半的磁场能量释放出来,因此这些等离子体团的碰撞能够产生一次伽玛暴。
[Abstract]:Coronal mass ejection is an explosive phenomenon on the surface of the sun, which enables magnetic flux rope and magnetized plasma to be rapidly ejected into the outer corona. During this process, enormous magnetic field energy is rapidly released and transformed into other forms of energy. It is generally thought that the driving mechanism is the catastrophe of magnetic structure and magnetic reconnection. Because the sun is the closest to the earth, and it is the most important star of mankind, the study of heliophysics, especially the solar burst activity which has an important influence on human life, has been deeply developed. In the field of high energy astrophysics, there are physical phenomena similar to coronal mass ejections. For example, the large flares of neutron stars and the intermittent jet generated by the black hole accretion disk system are the processes in which the system releases a large amount of magnetic energy and ejects material in a short period of time, and the details of these processes are unknown. Therefore, it is important to use the theory and model of solar bursts to study these unknown activities. The soft gamma ray recurrence source is considered to be a kind of magnetic neutron star. The large flare occurring in the soft gamma ray recovery source releases a great deal of energy in the short time scale. The energy sources driving these bursts are associated with the magnetic energy stored in the magnetosphere of the neutron star, and the trigger and drive mechanisms are the catastrophic instability and reconnection of the magnetic field structure. Referring to the theory and model of solar coronal mass ejections, we have developed an analytical theoretical model to explain the bright emission of magnetic neutron stars. In this model, the rotation and dislocation of the shell result in the distortion and deformation of the magnetic field, resulting in the formation of the flux rope in the magnetosphere and the accumulation of energy in the corresponding magnetic field configuration. When the energy and helicity stored in the magnetic field structure reach the threshold, the system will lose its equilibrium, the flux rope will be ejected outward in a catastrophic manner, and the magnetic reconnection will cause the catastrophe to evolve into a real explosion. Taking SGR1806-20 as an example, we calculate that the magnetic free energy (that is, the difference between the total magnetic energy of the system and the corresponding potential field energy) released during such an explosion is more than 1047 ergs, which is sufficient to drive a large flare. The released magnetic free energy is converted into radiation energy, kinetic energy and gravitational potential energy of magnetic flux rope. We also calculate the light variation curves of SGR1806-20,SGR0526-66 and SGR1900 14, and compare them with the observed data. Our calculated curves of light variation are in good agreement with the observed data. In many astrophysical black hole accretion disk systems, intermittent jets of plasma clusters have been observed, but their origin is unclear. Based on Yuan's model, we develop a magnetohydrodynamic model considering relativistic effects to explain intermittent jets in accretion disk systems of black holes. In this paper, we take SgrA* and constant star black hole as examples to study the dynamic characteristics of intermittent jet ion clusters. Our model results show that when the plasma mass is ejected, a large Lorentz factor can be obtained in a short period of time, and the plasma mass will continue to expand. Then, we further study the collision between plasma clusters which are ejected sequentially. It is found that the collisions between plasma clusters produced by a constant star black hole can occur, while the magnetic energy carried by a single plasma cluster is more than 1050 ergs. During the collision between two plasma clusters, about half of the magnetic field energy can be released by magnetic reconnection, so the collision of these plasmas can produce a gamma storm.
【学位授予单位】：中国科学院研究生院（云南天文台）
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P182;P14
本文编号：2464312
[Abstract]:Coronal mass ejection is an explosive phenomenon on the surface of the sun, which enables magnetic flux rope and magnetized plasma to be rapidly ejected into the outer corona. During this process, enormous magnetic field energy is rapidly released and transformed into other forms of energy. It is generally thought that the driving mechanism is the catastrophe of magnetic structure and magnetic reconnection. Because the sun is the closest to the earth, and it is the most important star of mankind, the study of heliophysics, especially the solar burst activity which has an important influence on human life, has been deeply developed. In the field of high energy astrophysics, there are physical phenomena similar to coronal mass ejections. For example, the large flares of neutron stars and the intermittent jet generated by the black hole accretion disk system are the processes in which the system releases a large amount of magnetic energy and ejects material in a short period of time, and the details of these processes are unknown. Therefore, it is important to use the theory and model of solar bursts to study these unknown activities. The soft gamma ray recurrence source is considered to be a kind of magnetic neutron star. The large flare occurring in the soft gamma ray recovery source releases a great deal of energy in the short time scale. The energy sources driving these bursts are associated with the magnetic energy stored in the magnetosphere of the neutron star, and the trigger and drive mechanisms are the catastrophic instability and reconnection of the magnetic field structure. Referring to the theory and model of solar coronal mass ejections, we have developed an analytical theoretical model to explain the bright emission of magnetic neutron stars. In this model, the rotation and dislocation of the shell result in the distortion and deformation of the magnetic field, resulting in the formation of the flux rope in the magnetosphere and the accumulation of energy in the corresponding magnetic field configuration. When the energy and helicity stored in the magnetic field structure reach the threshold, the system will lose its equilibrium, the flux rope will be ejected outward in a catastrophic manner, and the magnetic reconnection will cause the catastrophe to evolve into a real explosion. Taking SGR1806-20 as an example, we calculate that the magnetic free energy (that is, the difference between the total magnetic energy of the system and the corresponding potential field energy) released during such an explosion is more than 1047 ergs, which is sufficient to drive a large flare. The released magnetic free energy is converted into radiation energy, kinetic energy and gravitational potential energy of magnetic flux rope. We also calculate the light variation curves of SGR1806-20,SGR0526-66 and SGR1900 14, and compare them with the observed data. Our calculated curves of light variation are in good agreement with the observed data. In many astrophysical black hole accretion disk systems, intermittent jets of plasma clusters have been observed, but their origin is unclear. Based on Yuan's model, we develop a magnetohydrodynamic model considering relativistic effects to explain intermittent jets in accretion disk systems of black holes. In this paper, we take SgrA* and constant star black hole as examples to study the dynamic characteristics of intermittent jet ion clusters. Our model results show that when the plasma mass is ejected, a large Lorentz factor can be obtained in a short period of time, and the plasma mass will continue to expand. Then, we further study the collision between plasma clusters which are ejected sequentially. It is found that the collisions between plasma clusters produced by a constant star black hole can occur, while the magnetic energy carried by a single plasma cluster is more than 1050 ergs. During the collision between two plasma clusters, about half of the magnetic field energy can be released by magnetic reconnection, so the collision of these plasmas can produce a gamma storm.
【学位授予单位】：中国科学院研究生院（云南天文台）
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P182;P14
【参考文献】
相关期刊论文 前3条
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