KMS of Xinjiang Astronomical Observatory, CAS
| 中子星磁层活动及其对时变行为的影响 | |
| Alternative Title | Neutron star's magnetospheric activities and the corresponding effect for timing |
区子维
| |
| Subtype | 硕士 |
| Thesis Advisor | 丁国强 ; 仝号 |
| 2016 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 天体物理 |
| Keyword | 脉冲星 磁星 星风 |
| Abstract | 8 颗脉冲星有着小于3的制动指数。 222 颗脉冲星和15 颗磁星频率二阶导数的非正常分布。最近，相关研究发现PSR B0540?69 具有自转减慢态的改变: 突然的36% 的自转减慢态的增加。我们通过脉冲星星风制动模型来研究中子星磁层活动是如何影响上述三个现象。 PSR B0540?69 的持续态的制动指数是磁偶极辐射和粒子风的共同效应。粒子数密度反映了真实的磁层行为并和自转减慢行为有关。对应于PSR B0540?69 的36% 的自转减慢态的增加，相应的粒子数密度的增加在真空间隙模型为88% 。通过模型计算出来的制动指数在新态下为n = 1.79。另外，我们也可理解PSR J1846?0258 在星风模型下的时变行为。基于观测证据可知无论是脉冲星时变还是脉冲星辐射均反映了其磁层行为。对于真实的中子星磁层，涨落是无可避免的。年轻脉冲星具有有意义的制动指数，而年老脉冲星和磁星的涨落项主导着它们的频率二阶导数。脉冲星的制动指数和频率二阶导数可以被统一地解释。 8颗脉冲星的制动指数是磁偶极辐射和粒子风的共同作用所造成的。低制动指数的脉冲星对在中子星磁层中的粒子加速过程有着很强的限制。在脉冲星的长期自转演化当中，其死亡效应也应该被考虑。我们推导了一个与脉冲星自转减慢有关的方程，它和Brownian 运动中的Langevin 方程类似。磁星的磁层行为一般比正常脉冲星要强。 |
| Other Abstract | Eight pulsars have low braking indices that are less than 3. 222 pulsars and 15magnetars have abnormal distribution of frequency second derivatives. Recently, PSRB0540?69 is reported to have spin-down state changes: a 36% increase in the spindown rate. How neutron star magnetospheric activities affect these three phenomenaare investigated by using the wind braking model of pulsars. The persistent state braking index of PSR B0540?69 is the combined effect of magnetic dipole radiation andparticle wind. The particle density reflects the magnetospheric activity in real-timeand may be responsible for the changing spin-down behavior. Corresponding to the36% increase in the spindown rate of PSR B0540?69, the relative increase in the particle density is 88% in the vacuum gap model. The model calculated braking index inthe new state is n = 1.79. The variable timing behavior of PSR J1846?0258 is alsounderstandable in the pulsar wind model. It is based on the observational evidence thatpulsar timing is correlated with emission and both aspects reflect the magnetospheric activities. Fluctuations are unavoidable for a physical neutron star magnetosphere.Young pulsars have meaningful braking indices, while old pulsars’ and magnetars’fluctuation item dominates their frequency second derivatives. It can explain both thebraking index and frequency second derivative of pulsars uniformly. The braking indices of eight pulsars are the combined effect of magnetic dipole radiation and particlewind. During the lifetime of a pulsar, its braking index will evolve from three to one.Pulsars with low braking index may put strong constraint on the particle accelerationprocess. The effect of pulsar death should be considered during the long term rotational evolution of pulsars. An equation like the Langevin equation for Brownian motionwas derived for pulsar spin-down. The magnetospheric activities of magnetars arealways stronger than those of normal pulsars. |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xao.ac.cn/handle/45760611-7/1721 |
| Collection | 研究生学位论文 射电天文研究室 |
| Affiliation | 中国科学院新疆天文台 |
| Recommended Citation GB/T 7714 | 区子维. 中子星磁层活动及其对时变行为的影响[D]. 北京. 中国科学院大学,2016. |
| Files in This Item: | ||||||
| File Name/Size | DocType | Version | Access | License | ||
| 区子维-学位论文.pdf（1363KB） | 学位论文 | 暂不开放 | CC BY-NC-SA | Application Full Text | ||
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