arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0810.4135astro-ph
收藏

脉冲星射电辐射的偏振模式

Polarization Patterns in Pulsar Radio Emission

Mark M. McKinnon

摘要:

在庞加莱球的二维投影中显示射电望远镜单脉冲的偏振观测结果时,产生了各种有趣的偏振模式。在许多球面中,投影产生两个数据点簇,它们位于球面上的对映点。这些团簇是由偏振振幅的波动形成的,这些波动平行于代表脉冲星磁层中波传播模式的偏振态的单位矢量。然而,在其他的装饰物中,图案更复杂,类似于环形和领结或酒吧。这些复杂模式的形成还没有被理解,而且在很大程度上还没有被探索。脉冲星偏振的经验模型被用来表明,这些模式产生的偏振波动是垂直于模式矢量。该模型还表明,调制指数的偏振振幅是一个指标的偏振模式的复杂性。广义法拉第旋转的随机版本可以导致偏振矢量的方向波动,并且是模型中垂直波动的可能候选者。替代模型表明,一种模式经历垂直波动,而另一种则没有,这表明波动也可能是由于模式选择性随机过程,如磁层中的散射。的模式的偏振稳定性分析意味着,发射固有的过程是更有效地在去极化的发射比其偏振矢量的方向的波动。

英文摘要:

A variety of intriguing polarization patterns are created when polarization observations of the single pulses from radio pulsars are displayed in a two-dimensional projection of the Poincare sphere. In many pulsars, the projections produce two clusters of data points that reside at antipodal points on the sphere. The clusters are formed by fluctuations in polarization amplitude that are parallel to the unit vectors representing the polarization states of the wave propagation modes in the pulsar magnetosphere. In other pulsars, however, the patterns are more complex, resembling annuli and bow ties or bars. The formation of these complex patterns is not understood and largely unexplored. An empirical model of pulsar polarization is used to show that these patterns arise from polarization fluctuations that are perpendicular to the mode vectors. The model also shows that the modulation index of the polarization amplitude is an indicator of polarization pattern complexity. A stochastic version of generalized Faraday rotation can cause the orientation of the polarization vectors to fluctuate and is a possible candidate for the perpendicular fluctuations incorporated in the model. Alternative models indicate that one mode experiences perpendicular fluctuations and the other does not, suggesting that the fluctuations could also be due to a mode-selective random process, such as scattering in the magnetosphere. A polarization stability analysis of the patterns implies that processes intrinsic to the emission are more effective in depolarizing the emission than fluctuations in the orientation of its polarization vector.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑