Highly Resolved Self-Excited Density Waves in a Complex Plasma

Abstract

Experimental results on self-excited density waves in a complex plasma are presented. An argon plasma is produced in a capacitively coupled rf discharge at a low power and gas pressure. A cloud of microparticles is subjected to effective gravity in the range of 1-4 g by thermophoresis. The cloud is stretched horizontally (width/height approximately 45 mm/8 mm). The critical pressure for the onset of the waves increases with the temperature gradient. The waves are propagating in the direction of the ion drift. The wave frequency, phase velocity, and wavelength are measured, and particle migrations affected by the waves are analyzed at a time scale of 1 ms/frame and a subpixel space resolution.

Capacitively coupled rf discharge with a large amount of microparticles: Spatiotemporal emission pattern and microparticle arrangement

“…To obtain large volumetric microparticle clouds, we compensated the gravitational force by means of themophoresis [23]. To achieve this, we controlled the temperature difference between the bottom and top flanges [24] keeping the bottom flange about 17 K hotter than the top one. The microparticle cloud in the plasma was visualized by illuminating it with a sheet of a green (wavelength 532 nm) laser entering the chamber in its middle.…”

Numerical experiments on 2D strongly coupled complex plasmas

“…The second example [15] is to study the propagation of large amplitude dust-density waves (DDWs) [16] in 2D SCCPs and particle trapping therein, motivated by recent experimental observations of particle-wave interactions in SCCPs [17,18]. In our simulation, we use a rectangular geometry with confining boundary conditions in the x direction (also the wave propagation direction) and periodic boundary conditions in the y direction, and consider 3000 dust particles interacting via Yukawa potential Eq.(2).…”

Multistability, period doubling and traveling waves suppression by noise excitation in a nonlinear self-oscillatory medium with periodic boundary conditions

“…Примером автоколебательной среды может служить колебательная химическая реакция в большом объеме, различные части которого совершают колебания с различными амплитудами и фазами [1]. Периодические, квазипериодические и хаотические автоколеба-ния были обнаружены экспериментально и численно во многих распределенных системах различной природы и их математических моделях: в потоках жидкости [2,3], в плазме [4,5], в химических реакциях [1,6,7,8], в оптических системах [9,10], в биофизических объектах и живых тканях [11,12]. В силу разнообразия задач, связанных с автоколебательными сре-дами, и множества наблюдаемых явлений, несмотря на большое количество публикаций, поведение автоколебательных сред все еще не является в достаточной степени изученным.…”