标题： 由于太阳日冕中尖锐边界反射引起的射电爆发的去极化现象 显示英文标题

标题： Depolarization of radio bursts due to reflection off sharp boundaries in the solar corona

摘要： 有人认为，太阳射电爆发的去偏振现象需要在具有大密度比的区域之间反射厚度不超过一个波长（最多只有几米）的边界层。 由此暗示的不均匀性表明，日冕的结构远比从其他波长的观测所能解析的更为复杂和清晰。 磁流体理论的一个简化版本被用来推导去偏振系数：在处理色散时忽略了磁场的影响，但在处理（圆）偏振时考虑了磁场的影响。 通过绘制去偏振系数图来推断有效去偏振发生的条件，并得出结论，有利条件需要全内反射。 对于远离中心子午线的I型源，有效去偏振需要反射到密度比为$\xi\approx10$的过密结构上。 对于III型暴发，密度比为$\xi\approx2$就足够了，至少需要两次在径向方向上反射到管道壁上$\approx20^\circ$。 显示英文摘要

摘要： It is argued that depolarization of solar radio bursts requires reflection off boundary layers no thicker than about a wavelength (a few meters at most) between regions with large density ratios. The implied inhomogeneities suggest that the corona is much more highly and sharply structured than can be resolved from observations at other wavelengths. A simplified version of magnetoionic theory is used to derive a depolarization coefficient: the effect of the magnetic field is ignored in treating the dispersion, but taken into account in treating the (circular) polarization. Plots of the depolarization coefficient are used to infer conditions under which effective depolarization occurs, and it is concluded that favorable conditions require total internal reflection. For type I sources away from the central meridian, effective depolarization requires reflection off an overdense structure with a density ratio $\xi\approx10$. For type III bursts, a density ratio $\xi\approx2$ suffices, with at least two reflections off walls of ducts at $\approx20^\circ$ to the radial.