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  本文關(guān)鍵詞：r模對(duì)LMXB吸積中子星演化的影響　出處：《華中師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 中子星 r-模不穩(wěn)定性 粘滯 較差旋轉(zhuǎn) 環(huán)形磁場(chǎng)

【摘要】：認(rèn)識(shí)中子星的途徑有很多種,本文重點(diǎn)考慮r模不穩(wěn)定性。引力波輻射對(duì)模式的增長(zhǎng)效應(yīng)與粘滯耗散對(duì)模式的抑制效應(yīng)之問(wèn)的競(jìng)爭(zhēng)決定了r模不穩(wěn)定性能否產(chǎn)生。由于粘滯耗散時(shí)標(biāo)是依賴于溫度的,所以我們首先介紹中子星的熱演化方程,中子星一方面通過(guò)中微子輻射和表面光子輻射而釋放能量,另一方面,剪切粘滯耗散可以逐漸地把r模一部分振蕩能量轉(zhuǎn)化為熱能,并且低質(zhì)量X射線雙星(LMXB)中的吸積中子星通過(guò)吸積也可以產(chǎn)生熱能加熱星體。隨后,我們介紹了由星體的旋轉(zhuǎn)頻率和溫度這兩個(gè)物理量所決定的r模不穩(wěn)定性窗口,給出了典型的r模不穩(wěn)定性窗口以及LMXB中的吸積中子星在窗口中的演化,并根據(jù)觀測(cè)到的數(shù)據(jù),在考慮粘滯邊界層耗散效應(yīng)的基礎(chǔ)上,對(duì)窗口進(jìn)行了修正。我們通過(guò)求解線性和非線性流體力學(xué)方程得到的一階和二階r模演化方程,比較兩者之間的差異。較差旋轉(zhuǎn)能夠使得星體內(nèi)部的原初偶極磁場(chǎng)隨著流體元的漂移而被扭曲,這個(gè)過(guò)程導(dǎo)致了一種新的r模阻尼機(jī)制——磁阻尼。第三章中,我們?cè)诮o定星體內(nèi)部原初磁場(chǎng)位型的基礎(chǔ)上,結(jié)合二階拉格朗日位移,推導(dǎo)出了新的環(huán)向磁場(chǎng)以及磁能的變化率,給出了二階r模模型下的磁阻尼率。在此基礎(chǔ)上考察了磁阻尼率對(duì)LMXB中的吸積中子星的r模演化、熱演化以及旋轉(zhuǎn)演化的影響。結(jié)果表明,環(huán)形磁場(chǎng)的存在會(huì)抑制r模不穩(wěn)定性,使得星體自轉(zhuǎn)減慢,同時(shí)還會(huì)降低r模的加熱效果。隨后,進(jìn)一步考慮了由于磁場(chǎng)形變誘導(dǎo)星體產(chǎn)生引力波輻射,并在考慮粘滯邊界層的耗散作用的基礎(chǔ)上,再次考察了星體的演化。結(jié)果發(fā)現(xiàn)r模演化由之前長(zhǎng)時(shí)問(wèn)的振蕩演化變成迅速增長(zhǎng)并迅速衰減,這一變化時(shí)間持續(xù)大約幾千年,這是由于考慮磁場(chǎng)形變導(dǎo)致的引力波輻射制動(dòng)之后,吸積加速力矩不能和引力波制動(dòng)力矩相抗衡,星體會(huì)很快的自轉(zhuǎn)減慢,r模不會(huì)出現(xiàn)振蕩。我們得到結(jié)論LMXB中的r模作用瞬間完成,r模引力波輻射受到抑制,但是LXMB中的吸積中子星的演化還是受到了較大的影響,溫度演化、r模演化、旋轉(zhuǎn)演化都會(huì)體現(xiàn)突出特征,特別是旋轉(zhuǎn)極限頻率能夠與LMXB的觀測(cè)結(jié)果相符合。
[Abstract]:There are many ways to know neutron stars. In this paper, the instability of r mode is mainly considered. The competition between the increasing effect of gravitational wave radiation on the mode and the restraining effect of viscous dissipation on the mode determines whether the instability of r mode can be produced. Because the viscous dissipation time scale is dependent on the. Temperature. So we first introduce the thermal evolution equation of neutron star. On the one hand, neutron star releases energy through neutrino radiation and surface photon radiation, on the other hand. Shear viscosity dissipation can gradually convert part of the oscillatory energy of the r mode into heat energy, and the accretion neutron stars in the low mass X-ray binary star LMXB can heat the stars by heat energy through accretion. We introduce the r-mode instability window, which is determined by the rotation frequency and temperature of the star, and give the typical r-mode instability window and the evolution of the accretive neutron star in LMXB. Based on the observed data and considering the dissipative effect of viscous boundary layer, the window is modified. The first and second order r-mode evolution equations are obtained by solving linear and nonlinear hydrodynamic equations. The difference between the two is compared. The differential rotation can distort the primary dipole magnetic field along with the drift of the fluid element, which leads to a new r mode damping mechanism, magnetic damping. In Chapter 3. On the basis of a given initial magnetic field potential type in the body, combined with the second order Lagrange displacement, we derive the rate of change of the new toroidal magnetic field and magnetic energy. The influence of magnetic damping rate on the r mode evolution, thermal evolution and rotation evolution of accretion neutron stars in LMXB is investigated. The existence of annular magnetic field will suppress the instability of the r-mode, slow down the rotation of the star, and decrease the heating effect of the r-mode. Subsequently, the gravitational wave radiation of the star induced by magnetic field deformation will be further considered. On the basis of considering the dissipation of the viscous boundary layer, the evolution of the stars is studied again. It is found that the evolution of the r-mode changes from the oscillatory evolution of the previous long time to the rapid growth and decay. This change lasted for about several thousand years, because the accretion acceleration torque could not compete with the gravitational wave braking moment after considering the gravitational wave radiation braking caused by the magnetic field deformation, and the star would quickly slow down its rotation. It is concluded that the r-mode gravitational wave radiation in LMXB is suppressed instantly, but the evolution of accretive neutron stars in LXMB is still greatly affected. Both the temperature evolution and the rotation evolution show outstanding characteristics, especially the rotation limit frequency can be consistent with the observed results of LMXB.
【學(xué)位授予單位】：華中師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P145.6

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1 馬靜;r模對(duì)LMXB吸積中子星演化的影響[D];華中師范大學(xué);2015年

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本文編號(hào)：1358966