The effects of plasma lensing on the inferred dispersion measures of Fast Radio Bursts

摘要: Radio signals are delayed when propagating through plasma. This type of delay is frequency-dependent and usually used for estimating the projected number density electrons along line sight, called dispersion measure. The dense clumpy distribution plasma can cause refractive deflections radio signals, analogous to lensing effects. Similar gravitational lensing, there two contributions time effect in lensing: a geometric delay, due increased path length signal, dispersive change speed light medium. We show models distribution, point out that estimated measure be biased. Since contribution comparable bias measured dramatically large if effects not taken into account propagate high-density gradient clump