论文标题
等离子体镜头对快速无线电爆发的推断色散度量的影响
The effects of plasma lensing on the inferred dispersion measures of Fast Radio Bursts
论文作者
论文摘要
通过等离子体传播时，无线电信号会延迟。这种类型的延迟是频率依赖性的，通常用于估计沿视线的电子密度，称为分散度量。等离子体的致密和块状分布会引起无线电信号的折射，类似于镜头效应。与引力镜头类似，由于信号的路径长度增加而导致的等离子镜头的时间延迟效应有两种贡献：几何延迟以及由于血浆介质中光速的变化而导致的分散延迟。我们显示了两个等离子分布模型的延迟时间，并指出估计的分散度度量可能会偏差。由于几何效应的贡献可以与分散延迟的贡献相媲美，因此，如果不考虑血浆透镜效应时，当信号通过高密度梯度通过高密度的等离子体传播时，测量的分散度度量的偏差可能会大大较大。
Radio signals are delayed when propagating through plasma. This type of delay is frequency-dependent and is usually used for estimating the projected number density of electrons along the line of sight, called the dispersion measure. The dense and clumpy distribution of plasma can cause refractive deflections of radio signals, analogous to lensing effects. Similar to gravitational lensing, there are two contributions to the time delay effect in plasma lensing: a geometric delay, due to increased path length of the signal, and a dispersive delay due to the change of speed of light in a plasma medium. We show the delay time for two models of the plasma distribution, and point out that the estimated dispersion measure can be biased. Since the contribution of the geometric effect can be comparable to that of the dispersive delay, the bias in the measured dispersion measure can be dramatically large if plasma lensing effects are not taken into account when signals propagate through a high-density gradient clump of plasma.
