庫倫作用粒子之動力學; Dynamics of Coulomb-Interacting Particles

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/7208

Title:	庫倫作用粒子之動力學;Dynamics of Coulomb-Interacting Particles
Authors:	葉信杏;S-S Yeh
Contributors:	物理研究所
Keywords:	膠體懸浮粒子;微粒電漿;Colloidal liquid;dusty plasma
Date:	2000-07-19
Issue Date:	2009-09-22 10:52:20 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	在本論文中，我們用布朗動力學模擬庫倫作用粒子在二維空間的運動。觀察粒子位移平方對時間的變化以了解系統中單一粒子的擴散行為，發現在低溫時，粒子在短時間幾乎不受外力作用，隨著時間尺度增加，受其他粒子作用而被限制在一個區域做擾動，在長時間尺度下粒子做大位移的隨機跳躍。而隨著溫度的升高，粒子從短時間幾乎不受外力作用直接進入大位移的隨機跳躍。觀察粒子的位移分布，發現粒子花大部分的時間在被局限的區域做擾動，有時也會產生跳躍，使得系統中有一些較快的粒子產生而使粒子位移分布是一非高斯的分布。分別計算粒子間縱向跟橫向的空間相關函數，發現粒子同時做繩狀及渦形的集體運動並可測得其大小。 In this thesis, we perform Brownian dynamics simulations of Coulomb-interacting particles moving in a two dimensional space. We study the diusion property of a single particle by measuring the mean square displacement as a function of time. At short times the particles undergo unhindered self-diusion, at intermediate times they are hindered and conned in a cage formed by the neighbors, and at long times the large step hoppings occur. These three dierent motions are found in the melting state and the cage-eect disappears in the liquid state. We also study the mobility of the particles by measuring the displacement distribution and its deviation from Gaussian behavior. Non-Gaussian behavior is contributed by the hoppings occuring in the cage-eect region. Some faster particles and relaxation of cages are found at intermediate times. The shapes and sizes of cooperative motions are studied by examing the correlations among the particles displacements in both longitudinal and transverse directions. The string-like and vortex-like cooperative motions are both present and the sizes of the clusters are measured.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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