| 摘要: | 本計晝為期三年，延續擴展本實驗室近數年有關強耦合微粒電漿與複雜系統動力 行為系列研究。 懸浮於低壓電漿中的微米尺度微粒可透過其所攜大量負電荷強大庫倫交互作用 力，形成強耦合固體或液體結構，更可將此系統調控至氣體狀態，展現有趣的非線性 自發大振幅微粒電漿聲波。可用數位光學顯微系統長期追蹤粒子運動軌跡，以瞭解一 般非線性複雜多體系統中因尺度過小無法直接觀測的微動力問題。 近三年來，我們以實驗方式探研大振幅自發穩定的平行電漿聲波，首度發現並指 出如何透過調制不穩性（modulation instability)所造成的波形曲動（waveform undulation)而失穩，波面斷裂與重連，產生對偶沿低振幅洞絲(low amplitude hole filament)的缺陷絲與環繞其相反旋度的對偶電漿聲渦波（dust acoustic vortex)，首度 證實微粒電漿突波(rogue wave)的存在，及初步探討粒子如何透過與波的交互作用形 成高振幅突波(rogue wav)與缺陷。另一發面，我們以實驗與數值模擬方式探討微粒電 漿在焊冷後的晶化微觀動力行為，冷微粒電液體在外剪力下的崩盤式動力行為，桿狀 粒子液體冷卻後微結構與動力行為，與大腸桿菌及自驅動微粒紊流控制等研究。 本計晝延續前期計晝，深度探討微粒電漿突波、聲渦、與缺陷的相關性與動力行 為，在小體積微粒電漿團中，可否存在穩定單一的聲渦波；在較大驅動，更接近紊流 波狀態下，可否透過突波、聲渦波、與缺陷為建構其動力行為的基礎。並以數值模擬， 測試上述基礎激發態，可否於失穩氣體或其他電漿密度波中產生。以實驗探討微粒電 漿聲紊波中不同頻段模態如何交互作用。亦將透過數值模擬，探討超熱微粒電漿固體 所不同模態晶格振動間的交互作用，微粒喪失圓形對稱逐漸變長時，對凝固點附近的 液體或固體基礎微結構與微觀動力行為的影響，及展開細胞細胞穿透不同硬度基材的 動力行為及細胞間交互作用研究。 上述議題不僅對微粒電漿物理領域重要，更有助瞭解其他相關的非線性複雜系統 中的非線性行為。研究主要將以實驗方式進行，並配合進行部分數值模擬。 ;This 3-year project continues our series researches on the dynamics of dusty plasmas and complex systems. The dusty plasma composed of negative charged dust particles suspended in a low pressure discharge is a strongly coupled complex system. It can be tuned from the solid to the gas state which supports self-excited dust acoustic waves with longitudinal dust particle oscillation. The capability of monitoring and correlating large area dust density fluctuation and particle motions makes it a good platform to understand the generic dynamical behaviors of nonlinear density waves in gases and plasmas. In the past three years, we experimentally demonstrated the first observations of singular events such as the low amplitude hole filaments coinciding with defect filaments, the surrounding acoustic vortex pairs with opposite helicities, and the nearby spatio-temporally uncertain rogue wave events in weakly disordered self-excited dust acoustic waves. We constructed Eulerian-Lagrangian picture from the wave-particle interaction view to understand the key origins for the formation of those singular events. Moreover, we experimentally and numerically explored crystallization microdynamics of quenched Yukawa liquids, the seismic like micro-structural rearrangement in weakly sheared ultra-cold dusty plasma liquids, and the dynamics of passive and active rod-like particles such as dense E-Coli suspensions in liquids. In this new project, extending from past researches we will conduct the following researches: a) the spatio-temporal correlation of amplitude hole filaments, rogue waves, and acoustic vortices, b) whether they can be used as fundamental excitations to understand and characterize more disordered 3D nonlinear dust acoustic waves, c) whether they can be found in other simpler weakly disordered density waves in plasmas or gases, d) whether a single stable acoustic vortex can be excited in a small dusty plasma cluster and the angular momentum it carries, e) the mode-mode interaction of dust acoustic wave turbulence, f) the mode-mode coupling of superheated dusty plasma crystal, g) the micro-structure and motion of dense spherocylinders (i.e. rods with two hemispherical ends) around the freezing points under various aspect ratio close to one, h) the dynamical behaviors of cells, their correlation with extracellular matrix stiffness and interaction with other cells. The frontier studies on the above unexplored issues are not only important for the dusty plasma physics, but also should be able to shed some light on understanding the generic nonlinear behaviors in other corresponding nonlinear extended complex systems. The investigation will be conducted mainly experimentally and partially numerically. |
