论文标题
粘性流体壳对重力波的传播的影响
Effect of a viscous fluid shell on the propagation of gravitational waves
论文作者
论文摘要
在本文中，我们表明在某些情况下，通过粘性液传播的引力波（GWS）的阻尼可能非常重要。特别是，这适用于核心塌陷超新星（CCSNE）。在以前的工作中，我们在邦迪 - 萨克斯形式主义内的固定背景上使用了线性化扰动，以确定尘埃壳对GW传播的影响。在这里，我们从物质的（先前发现的）速度场开始，然后使用它来确定流体流的剪切张量。然后，对于粘性流体，计算出耗散的能量，导致GW阻尼方程。发现当波长$λ$比物质外壳的半径$ r_i $小得多时，阻尼效果与先前的结果一致；但是，如果$λ\ gg r_i $，那么阻尼效果将大大增加。 接下来，本文讨论了天体物理应用CCSNE。有几种不同的物理过程会产生GW，文献中已经介绍了许多模型。因此，需要使用每个参数$λ，r_i $和具有一系列值的剪切粘度$η$的系数来评估阻尼效果。发现在大多数情况下，会有大量的阻尼，在某些情况下，它几乎完成了。 我们还考虑了粘性阻尼对早期宇宙通货膨胀期间产生的原始引力波（PGW）的影响。研究波长比壳半径较短或更长的情况，研究了两种情况。我们发现，有些条件会产生明显的阻尼，以至于无法检测到波浪。
In this paper we show that there are circumstances in which the damping of gravitational waves (GWs) propagating through a viscous fluid can be highly significant; in particular, this applies to Core Collapse Supernovae (CCSNe). In previous work, we used linearized perturbations on a fixed background within the Bondi-Sachs formalism, to determine the effect of a dust shell on GW propagation. Here, we start with the (previously found) velocity field of the matter, and use it to determine the shear tensor of the fluid flow. Then, for a viscous fluid, the energy dissipated is calculated, leading to an equation for GW damping. It is found that the damping effect agrees with previous results when the wavelength $λ$ is much smaller than the radius $r_i$ of the matter shell; but if $λ\gg r_i$, then the damping effect is greatly increased. Next, the paper discusses an astrophysical application, CCSNe. There are several different physical processes that generate GWs, and many models have been presented in the literature. The damping effect thus needs to be evaluated with each of the parameters $λ,r_i$ and the coefficient of shear viscosity $η$, having a range of values. It is found that in most cases there will be significant damping, and in some cases that it is almost complete. We also consider the effect of viscous damping on primordial gravitational waves (pGWs) generated during inflation in the early Universe. Two cases are investigated where the wavelength is either much shorter than the shell radii or much longer; we find that there are conditions that will produce significant damping, to the extent that the waves would not be detectable.
