Astrophysical explosions that contain dense and ram-pressure-dominated ejecta evolve through an interaction phase, during which a forward shock (FS), contact discontinuity (CD), and reverse shock (RS) form and expand with time. We describe new self-similar solutions that apply to this phase and are most accurate in the limit that the ejecta density is large compared to the ambient density. These solutions predict that the FS, CD, and RS expand at different rates in time and not as single temporal power laws, are valid for explosions driven by steady winds and homologously expanding ejecta, and exist when the ambient density profile is a power law with a power-law index shallower than ∼3 (specifically when the FS does not accelerate). We find excellent agreement between the predictions of these solutions and hydrodynamical simulations, both for the temporal behavior of the discontinuities and for the variation of the fluid quantities. The self-similar solutions are applicable to a wide range of astrophysical phenomena and—although the details are described in future work—can be generalized to incorporate relativistic speeds with arbitrary Lorentz factors. We suggest that these solutions accurately interpolate between the initial “coasting” phase of the explosion and the later, energy-conserving phase (or, if the ejecta is homologous and the density profile is sufficiently steep, the self-similar phase described in R. A. Chevalier).

中文翻译：

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从滑行到节能：强爆炸相互作用阶段的新型自相似解决方案


包含致密和冲压压力主导的喷射物的天体物理爆炸会经历一个相互作用阶段，在此期间，正向激波 （FS）、接触不连续性 （CD） 和反向激波 （RS） 会随着时间的推移而形成和膨胀。我们描述了适用于该相的新的自相似解，并且在喷射物密度与环境密度相比较大的极限下最准确。这些解决方案预测 FS、CD 和 RS 以不同的时间速率膨胀，而不是作为单一的时间幂律，对于由稳态风和同源膨胀喷射物驱动的爆炸有效，并且当环境密度分布是幂律指数低于 ∼3 的幂律时（特别是当 FS 不加速时）时存在。我们发现这些解的预测与流体动力学模拟之间非常一致，无论是对于不连续性的时间行为还是流体量的变化。自相似解适用于广泛的天体物理现象，并且 - 尽管细节将在未来的工作中描述 - 可以推广以包含相对论速度和任意洛伦兹因子。我们建议这些解决方案在爆炸的初始“滑行”阶段和随后的能量守恒阶段之间准确插值（或者，如果喷射物是同源的并且密度分布足够陡峭，则为 R. A. Chevalier 中描述的自相似阶段）。