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arXiv 1704.04873math.PRcs.NAmath.APmath.NA
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凝聚粒子系统及其在非线性福克-平克方程中的应用

Coalescing particle systems and applications to nonlinear Fokker-Planck equations

University of Arizona(亚利桑那大学)

Gleb Zhelezov, Ibrahim Fatkullin

AI总结:

本文研究了具有对数奇异相互作用势的随机粒子系统,通过将平方贝塞尔过程与局部粒子簇的演化联系起来,提出了一种能够检测多点粒子碰撞的数值方法,应用于非线性福克-平克方程,如帕塔克-凯勒-塞格尔模型及其多物种变体。

摘要:

我们研究了一种具有对数奇异相互作用势的随机粒子系统,允许非弹性粒子碰撞。我们将平方贝塞尔过程与局部粒子簇的演化联系起来,并开发了一种能够检测多点粒子碰撞的数值方法,而无需进行成对计算或非常精细的自适应时间步长。我们证明,当系统处于适当的参数域时,经验质量密度的水动力极限是非线性福克-平克方程的解,例如帕塔克-凯勒-塞格尔(PKS)模型或其多物种变体。然后我们证明所提出的数值方法适用于模拟PKS中有限时间奇点的形成,以及PKS前爆破和后爆破动态。此外,我们展示了在两物种凯勒-塞格尔系统中,总二次矩增加的爆破现象中,一个成分的二次矩线性增加,另一个成分的二次矩线性减少。

英文摘要:

We study a stochastic particle system with a logarithmically-singular inter-particle interaction potential which allows for inelastic particle collisions. We relate the squared Bessel process to the evolution of localized clusters of particles, and develop a numerical method capable of detecting collisions of many point particles without the use of pairwise computations, or very refined adaptive timestepping. We show that when the system is in an appropriate parameter regime, the hydrodynamic limit of the empirical mass density of the system is a solution to a nonlinear Fokker-Planck equation, such as the Patlak-Keller-Segel (PKS) model, or its multispecies variant. We then show that the presented numerical method is well-suited for the simulation of the formation of finite-time singularities in the PKS, as well as PKS pre- and post-blow-up dynamics. Additionally, we present numerical evidence that blow-up with an increasing total second moment in the two species Keller-Segel system occurs with a linearly increasing second moment in one component, and a linearly decreasing second moment in the other component.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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