太陽爆發(fā)理論和模型在高能天體物理研究中的應用
發(fā)布時間：2019-04-24 08:45
【摘要】：日冕物質拋射是太陽表面的一種爆發(fā)現象,它可以使磁通量繩和磁化等離子體快速地拋射到外層日冕。在這個過程中巨大的磁場能量迅速釋放,并轉化為其他形式的能量。人們通常認為它的驅動機制主要為磁結構的災變和磁重聯。由于太陽是離地球最近的,而且是對人類最重要的一顆恒星,太陽物理,特別是對人類生活有重要影響的太陽爆發(fā)活動的研究得到了深入的發(fā)展。 在高能天體物理領域中,也存在著與日冕物質拋射相類似的物理現象。例如,磁中子星的大耀發(fā)以及黑洞吸積盤系統產生的間歇性噴流等,這些都是系統在短時間內釋放大量的磁能并拋射物質的過程,而這些過程的具體細節(jié)還不被人們所知。因此,運用太陽爆發(fā)的相應理論和模型來對這些未知的活動進行研究,具有重要的借鑒作用。 軟伽馬射線復現源被認為是磁中子星的一種,發(fā)生在軟伽馬射線復現源中的大耀發(fā)在短時標內釋放出巨大的能量。驅動這些爆發(fā)的能量來源與于貯存在磁中子星磁球層內的磁場能量,而觸發(fā)和驅動機制則為磁場結構的災變不穩(wěn)定性和磁重聯。參考太陽日冕物質拋射的理論和模型,我們發(fā)展了一個解析的理論模型來解釋磁中子星的大耀發(fā)。在這個模型中,殼層的轉動和錯位造成磁場的扭曲和變形,導致磁通量繩在磁球層中形成以及能量在相應的磁場位形中積累。當儲存在磁場結構中的能量和螺度達到了閾值,系統就會失去平衡,磁通量繩被以災變的方式向外拋射,而磁重聯使災變演化成真正的爆發(fā)。以SGR1806-20為例,我們計算了在這樣一次爆發(fā)過程中所釋放出的磁自由能(即系統的總磁能和相應勢場能量之差)大于1047爾格,足以驅動一次大耀發(fā)。釋放的磁自由能被轉化為輻射能、磁通量繩的動能和引力勢能。我們還計算了SGR1806-20、SGR0526-66和SGR1900+14這三次大耀發(fā)過程的光變曲線并將他們與觀測數據相比較。我們計算得出的光變曲線能很好地與觀測數據符合。 在許多天體物理中的黑洞吸積盤系統中,由等離子體團構成的間歇性噴流已經被觀測到,但是他們的起源還不清楚。以Yuan等人的模型為基礎,我們發(fā)展了一個考慮了相對論效應的磁流體動力學模型來解釋黑洞吸積盤系統中的間歇性噴流。我們以SgrA*和恒星級黑洞為例子,研究等間歇性噴流離子體團的動力學特征。我們的模型結果表明,等離子體團被拋射出去后,可以在短時間內獲得很大的洛侖茲因子,并且不斷地發(fā)生膨脹。然后,我們進一步地研究了相繼拋射的等離子體團間的碰撞,發(fā)現恒星級黑洞產生的等離子體團之間可以發(fā)生碰撞,而單個等離子體團所攜帶的磁能大于1050爾格。在兩個等離子體團的相互碰撞過程中,通過磁重聯可將大約一半的磁場能量釋放出來,因此這些等離子體團的碰撞能夠產生一次伽瑪暴。
[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.
【學位授予單位】：中國科學院研究生院（云南天文臺）
【學位級別】：博士
【學位授予年份】：2014
【分類號】：P182;P14
本文編號：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.
【學位授予單位】：中國科學院研究生院（云南天文臺）
【學位級別】：博士
【學位授予年份】：2014
【分類號】：P182;P14
【參考文獻】
相關期刊論文 前3條
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2 ;Energetics and Propagation of Coronal Mass Ejections in Different Plasma Environments[J];Chinese Journal of Astronomy and Astrophysics;2002年06期
3 溫學詩 ,吳鑫基;已獲輝煌 繼續(xù)輝煌——脈沖星研究的科學意義[J];現代物理知識;1995年04期
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