本文選題：吸積盤 + 自生磁場　； 參考：《南昌大學》2013年博士論文

【摘要】：早在上世紀二十年代,吸積盤理論就被用于研究太陽星云的形成及演化,1969年,Lynden-Bell開創(chuàng)性地利用該理論解釋了類星體的能源機制,使得吸積盤理論的應用得到突破性進展。時至今日,吸積盤理論依然是等離子體天體物理研究的熱點課題之一。從物理學角度來講,吸積盤的形成存在兩個重要的物理過程：物質向內(nèi)吸積以及角動量向外轉移。盤的結構與演化依賴于角動量的轉移,而盤中黏滯的大小及其性質正是決定角動量轉移的重要因素。換言之,吸積盤的結構及其演化取決于盤中的黏滯。然而,純粹的分子黏滯不可能實現(xiàn)吸積盤中角動量轉移過程,吸積盤非�？赡芴幱谕膭訝顟B(tài)。上世紀七十年代,Shakura與Sunyaev引入湍動黏滯的概念,并建立標準薄盤模型,亦稱SSD模型,使得吸積盤理論由過去的定性及半定量描述上升到定量描述的理論高度。然而SSD模型是一個參量化的唯象模型,它掩蓋了湍動黏滯的本質,人們無法從中得到更多有關湍動的信息。因此,天體物理學家必須尋找一種能夠揭示湍動黏滯物理本質的新模型。 2002年,李曉卿和張航從動力論出發(fā),考慮到波-波、波-粒相互作用,理論計算得到非相對論性等離子體中橫等離激元產(chǎn)生的低頻自生磁場方程。調制不穩(wěn)定性分析表明這種磁場具有大的不穩(wěn)定性增率,能夠坍塌到局域小尺度范圍內(nèi),形成空間高度間歇的強磁流,呈現(xiàn)湍動狀態(tài)。這些強磁流元之間以及磁流元與周圍介質之間的相互作用是吸積盤中反常黏滯產(chǎn)生的本質。本論文首先利用這種新的反常磁黏滯機制,分別研究了年輕恒星周圍磁化薄吸積盤以及原恒星盤的結構與不穩(wěn)定性。結果表明,利用反常黏滯模型能夠得到與觀測相吻合的溫度分布及更接近真實的盤結構,這使得穩(wěn)定性分析更有意義。 本論文研究內(nèi)容之二是基于李曉卿等人得到的相對論性等離子體中自生磁場非線性控制方程,找到自生磁場的自類似坍塌解；從間歇磁流間相互作用的麥克斯韋應力張量出發(fā),把反常黏滯理論推廣至相對論框架,理論推導得到相對論性吸積盤中的反常磁黏滯運動學系數(shù)。結果表明,相對論性吸積盤中的反常黏滯系數(shù)對電子有效溫度的依賴關系與非相對論中的情況截然不同。 其三,對李曉卿等人引力橫等離激元相互作用產(chǎn)生自生甚低頻磁型引力場耦合方程進行調制不穩(wěn)定性分析。分析表明,自生引力磁場是調制不穩(wěn)定的,并通過數(shù)值擬合計算出調制不穩(wěn)定性最大增長率及對應的最大波數(shù),找到引力磁場坍塌的自類似解；理論計算得到自引力吸積盤中的反常磁黏滯運動學系數(shù)；與分子黏滯比較發(fā)現(xiàn),反常磁黏滯強于分子黏滯約八個量級,足以提供自引力盤中物質吸積及角動量轉移所需的吸積率,這與文獻中給出的結果相吻合。 吸積盤中反常磁黏滯模型明確揭示了湍動黏滯產(chǎn)生的物理機制,有助于研究天體物理吸積盤中非線性過程；同時也為實驗和模擬提供理論指導。
[Abstract]:In the early 20s, the accretion disk theory has been used to study the formation and evolution of the solar nebula, 1969, Lynden-Bell creatively use the theory to explain the energy mechanism of quasars, the application of accretion disk theory has a breakthrough. Today, the accretion disk theory is still one of the hot research topics in plasma astrophysics from the physics point of view, the formation of an accretion disk has two important processes: material inward accretion and angular momentum outwards. The structure and evolution of the disk transfer depends on the angular momentum, and the size and nature of plate stick lag is an important factor that decides the transfer of angular momentum. In other words, the structure of accretion the disc and its evolution depends on the disc viscosity. However, pure molecular viscosity can not be achieved in accretion disks, angular momentum transfer process, the accretion disk may be in very turbulent state. In 70s, Shakura and Sunyaev introduced the concept of turbulent viscosity, and the establishment of the standard thin disk model, called SSD model, and by semi quantitative qualitative description of the past to rise to the level of theory makes the quantitative description of the accretion disk theory. However, the SSD model is a parametric phenomenological model, it obscures the nature of turbulence the dynamic viscosity, people can get more information about the turbulence from it. Therefore, astrophysicists have to search for a new model to reveal the physical nature of the turbulent viscosity.
In 2002, Li Xiaoqing and Zhang hang from the view of power, taking into account the wave wave and wave particle interaction, calculated the non relativistic low frequency transverse plasma plasmons generated spontaneous magnetic field equation. The analysis shows that this magnetic field has increased rate of instability of modulation instability can be collapsed into local small scale range, strong magnetic forming highly intermittent flow, showing the turbulent state. The strong magnetic element between the flow and magnetic interaction between the element and the surrounding medium is the essence of the accretion disks of anomalous viscosity produced. Firstly, using the new anomalous magnetic viscosity mechanism, and instability of structure are studied the magnetization of thin accretion disks around young stars and a protostellar disk. The results show that the anomalous viscosity model can obtain the temperature distribution is consistent with the observations and more close to the real plate structure, which makes the stability of points It is more meaningful to analyze.
The content of this paper is the two magnetic field nonlinear equations of authigenic relativistic plasma obtained by Li Xiaoqing et al found based on self generated magnetic field self similar collapse solution; starting from the Maxwell stress tensor intermittent flux interactions, the anomalous viscosity theory extends to the relativistic framework, the theoretical derivation of anomalous magnetic relativity the viscosity of the accretion disk kinematics coefficient. The results show that the dependence of anomalous viscosity coefficient of relativistic accretion disk on the electron effective temperature and non relativity in different situation.
Third, analysis of authigenic VLF magnetic gravitation field coupling equation of modulation instability of Li Xiaoqing gravity transverse plasmons interaction. Analysis shows that the gravitational field is self modulation instability, and through numerical fitting to calculate the maximum modulation instability wave number maximum growth rate and the gravitational collapse of the magnetic field is found the self similar solution; calculated the anomalous magnetic self gravitating accretion disk kinematics viscosity coefficient; and molecular viscosity comparison found that the anomalous magnetic viscosity is stronger than the molecular viscosity of about eight orders of magnitude, enough to provide the required material from the accretion disk accretion and the gravitational angular momentum transfer rate, which is consistent with the literature the results given in.
The anomalous magnetic viscosity model in accretion disk clearly reveals the physical mechanism of turbulent viscous generation, and helps to study the nonlinear process in astrophysical accretion disks. It also provides theoretical guidance for experiments and simulations.

【學位授予單位】：南昌大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：P142

【參考文獻】

相關期刊論文 前1條

1 楊蘭田,劉超;吸積盤整理論及其在天體物理中的應用[J];自然雜志;1986年07期

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本文編號：1746022