本文選題：吸積盤 + 自生磁場(chǎng)　； 參考：《南昌大學(xué)》2013年博士論文

【摘要】：早在上世紀(jì)二十年代,吸積盤理論就被用于研究太陽(yáng)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(jī)制,使得吸積盤理論的應(yīng)用得到突破性進(jìn)展。時(shí)至今日,吸積盤理論依然是等離子體天體物理研究的熱點(diǎn)課題之一。從物理學(xué)角度來(lái)講,吸積盤的形成存在兩個(gè)重要的物理過(guò)程：物質(zhì)向內(nèi)吸積以及角動(dòng)量向外轉(zhuǎn)移。盤的結(jié)構(gòu)與演化依賴于角動(dòng)量的轉(zhuǎn)移,而盤中黏滯的大小及其性質(zhì)正是決定角動(dòng)量轉(zhuǎn)移的重要因素。換言之,吸積盤的結(jié)構(gòu)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(shí)現(xiàn)吸積盤中角動(dòng)量轉(zhuǎn)移過(guò)程,吸積盤非�？赡芴幱谕膭�(dòng)狀態(tài)。上世紀(jì)七十年代,Shakura與Sunyaev引入湍動(dòng)黏滯的概念,并建立標(biāo)準(zhǔn)薄盤模型,亦稱SSD模型,使得吸積盤理論由過(guò)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(gè)參量化的唯象模型,它掩蓋了湍動(dòng)黏滯的本質(zhì),人們無(wú)法從中得到更多有關(guān)湍動(dòng)的信息。因此,天體物理學(xué)家必須尋找一種能夠揭示湍動(dòng)黏滯物理本質(zhì)的新模型。 2002年,李曉卿和張航從動(dòng)力論出發(fā),考慮到波-波、波-粒相互作用,理論計(jì)算得到非相對(duì)論性等離子體中橫等離激元產(chǎn)生的低頻自生磁場(chǎng)方程。調(diào)制不穩(wěn)定性分析表明這種磁場(chǎng)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(qiáng)磁流,呈現(xiàn)湍動(dòng)狀態(tài)。這些強(qiáng)磁流元之間以及磁流元與周圍介質(zhì)之間的相互作用是吸積盤中反常黏滯產(chǎn)生的本質(zhì)。本論文首先利用這種新的反常磁黏滯機(jī)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(jié)構(gòu)與不穩(wěn)定性。結(jié)果表明,利用反常黏滯模型能夠得到與觀測(cè)相吻合的溫度分布及更接近真實(shí)的盤結(jié)構(gòu),這使得穩(wěn)定性分析更有意義。 本論文研究?jī)?nèi)容之二是基于李曉卿等人得到的相對(duì)論性等離子體中自生磁場(chǎng)非線性控制方程,找到自生磁場(chǎng)的自類似坍塌解；從間歇磁流間相互作用的麥克斯韋應(yīng)力張量出發(fā),把反常黏滯理論推廣至相對(duì)論框架,理論推導(dǎo)得到相對(duì)論性吸積盤中的反常磁黏滯運(yùn)動(dòng)學(xué)系數(shù)。結(jié)果表明,相對(duì)論性吸積盤中的反常黏滯系數(shù)對(duì)電子有效溫度的依賴關(guān)系與非相對(duì)論中的情況截然不同。 其三,對(duì)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(chǎng)耦合方程進(jìn)行調(diào)制不穩(wěn)定性分析。分析表明,自生引力磁場(chǎng)是調(diào)制不穩(wěn)定的,并通過(guò)數(shù)值擬合計(jì)算出調(diào)制不穩(wěn)定性最大增長(zhǎng)率及對(duì)應(yīng)的最大波數(shù),找到引力磁場(chǎng)坍塌的自類似解；理論計(jì)算得到自引力吸積盤中的反常磁黏滯運(yùn)動(dòng)學(xué)系數(shù)；與分子黏滯比較發(fā)現(xiàn),反常磁黏滯強(qiáng)于分子黏滯約八個(gè)量級(jí),足以提供自引力盤中物質(zhì)吸積及角動(dòng)量轉(zhuǎn)移所需的吸積率,這與文獻(xiàn)中給出的結(jié)果相吻合。 吸積盤中反常磁黏滯模型明確揭示了湍動(dòng)黏滯產(chǎn)生的物理機(jī)制,有助于研究天體物理吸積盤中非線性過(guò)程；同時(shí)也為實(shí)驗(yàn)和模擬提供理論指導(dǎo)。
[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(xué)位授予單位】：南昌大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2013
【分類號(hào)】：P142

【參考文獻(xiàn)】

相關(guān)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(yīng)用[J];自然雜志;1986年07期

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本文編號(hào)：1746022