Bent Marshak waves
Bent Marshak waves
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DOI：
10.1063/1.2388268
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发表时间：
2005-10
影响因子：
2.2
通讯作者：
O. Hurricane;J. Hammer
中科院分区：
文献类型：
--
作者：
O. Hurricane;J. Hammer
辐射驱动的热波（马沙克波）在天体物理学和地面激光驱动的高能密度等离子体物理实验中普遍存在。一般来说，描述马沙克波的方程是如此非线性，以至于涉及多个空间维度的解需要模拟。然而，本文证明了利用与壁面反照率有关的参数的渐近展开和热锋运动方程的简化，可以解析地解决以有耗壁面为界的马尔沙克波的二维非线性演化问题。三个参数决定了非线性演化：修正的Markshak扩散常数、与壁反照率相关的小参数和壁间距。最后的非线性解表明，非理想边界会使马沙克波变慢并发生弯曲。在一个完美边界的极限下，解恢复原来的马尔沙克类扩散解。将解析解与有限的模拟结果和实验数据进行比较。
Radiation-driven heat waves (Marshak waves) are ubiquitous in astrophysics and terrestrial laser-driven high-energy density plasma physics experiments. Generally, the equations describing Marshak waves are so nonlinear, that solutions involving more than one spatial dimension require simulation. However, in this paper it is shown that one may analytically solve the problem of the two-dimensional nonlinear evolution of a Marshak wave, bounded by lossy walls, using an asymptotic expansion in a parameter related to the wall albedo and a simplification of the heat front equation of motion. Three parameters determine the nonlinear evolution: a modified Markshak diffusion constant, a smallness parameter related to the wall albedo, and the spacing of the walls. The final nonlinear solution shows that the Marshak wave will be both slowed and bent by the nonideal boundary. In the limit of a perfect boundary, the solution recovers the original diffusion-like solution of Marshak. The analytic solution will be compared to a limited set of simulation results and experimental data.