Weakly nonlinear gravitational instability for arbitrary Omega
Weakly nonlinear gravitational instability for arbitrary Omega
复制标题
任意 Omega 的弱非线性引力不稳定性
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
R. Pellat
中科院分区：
文献类型：
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作者：
F. Bouchet;R. Juszkiewicz;S. Colombi;R. Pellat
研究了宇宙常数为零的Friedmann-Lemaitre模型中粒子轨迹的弱非线性演化。该物质被认为是一种非相对论的无压流体。利用拉格朗日坐标下的微扰展开，导出了具有任意密度参数Ω的二阶解的解析表达式。如果位移场的梯度很小，这种微扰展开是有效的，这是一个比通常欧拉要求的密度微扰小得多的条件。
The weakly nonlinear evolution of particle trajectories in Friedmann-Lemaitre models with zero cosmological constant is investigated. The matter is assumed to be a nonrelativistic pressureless fluid. A perturbative expansion in Lagrangian coordinates is used and analytic expressions for the second-order solutions with arbitary density parameter Ω are derived. This perturbative expansion is valid provided the gradients of the displacement field are small, a much weaker condition than the usual Eulerian requirement of smallness of the density perturbations