Self-Organization and the Physics of Entropy Expulsion

本研究的最终目的是建立自然界中有序是如何自发产生的普遍概念，即自组织。到目前为止，我们广泛的模拟研究使我们提出了一个场景，即自组织中有三个关键过程。第一个是系统的内在非线性，第二个是来自外部世界的能量（信息）供应过程，第三个是从系统中排出产生的多余量（熵）的过程。在本研究中，重点研究了产生的熵是被限制在系统内还是被排除在系统外的差异是如何影响自组织的。这是通过以离子-声学双层形成为例来实现的，其中热电子以低于电子热速度的相对速度相对于低温离子流动。为此，建立了开放边界颗粒模拟模型，在该模型中，连续提供形状平缓的新鲜颗粒，在边界处过滤掉系统内部产生的脏颗粒，以保持净通量常数。研究发现，与之前的周期系统中微弱的、短暂的、因而具有熵储备的势结构相比，产生了具有极长寿命的巨大的类激波无碰撞势结构。与传统的弱（“正常”）离子声双层结构相比，这种巨大的电位结构被命名为“超级”离子声双层。这一新发现的结论是，正如我们所断言的那样，当熵被排除在外时，自组织可以非常活跃地发生。换句话说，目前的研究无疑为促进我们假设的自组织情景迈出了一大步。

The ultimate goal of this research is to establish the universal concept of how an orderliness is spontaneously created in nature, namely, self-organization. Our extensive simulation studies so far have led us to propose a scenario that there are three key processes in self-organization. The first is the intrinsic nonlinearity of a system, the second is the process of energy (information) supply from the external world, and the third is the process of expulsion of produced superfluous quantities (entropy) from the system.In this research particular emphasis is placed on investigating how the self-organization is influenced by the difference of whether the produced entropy is confined within the system or expulsed from it. This is done by taking as an example the ion-acoustic double layr formation, where hot electrons are streaming relatively to low temperature ions with a relative speed less than the electron thermal speed. For this purpose an open boundary particle simulation model is developed where fresh particles with a gently-shaped distribution are continuously supplied and dirty particles produced inside the system are filtered out at the boundaries so as to maintain a net flux constant.It is discovered that gigantic shock-like collisionless potential structure is created with an extreamly long lifetime, in contrast to a weak, short-lived potential structure in the previous periodic, thus, entropy-reseved system. This gigantic potential structure is named as "super" ion-acoustic double layr compared to the conventional weak ("normal") ion-acoustic double layr. This new discovery concludes that, as we assert, when entropy is expelled, self-organization can take place much vigorously. In other words, the present research has definitely contributed a big step forward to promoting our hypothesized scenario of self-organization.