Particle Motion In A Dusty Plasma Metal Ratchet

Dusty plasma is composed of electrons,ions,neutral gases and dust particles,which is an active branch in the field of plasma physics in recent years.Dust particles are charged by colliding with plasma electrons and ions,in the plasma environment.At the same time,dust particles interact with plasma to absorb energy and convert it into particle kinetic energy.However,dust particles usually move randomly,and the energy obtained cannot be effectively collected and utilized.Rectifying the random motion of dust particles to form a directional motion is of great research value for both the fundamental research of dust plasma physics and the potential application of energy collection.The concept of dusty plasma ratchet has been put forward in the early stage,a resin experiment device has been designed,and the controllable rectification of dust particles has been realized,that is,the random movement of dust particles is rectified to directional movement in the plasma environment.It has been found that the ratchet potential formed by resin ratchet played a very important role in the rectification of particles.Because the ratchet potential of resin ratchet is different from that of metal conductor ratchet,how about the rectification of dust particles in metal ratchet? This is the focus of this work.Based on the ratchet model of dust plasma,the movement of dust particles in the ratchet and ring gear,and the rectification of particles with different properties are studied by experiments and simulations.The results show that: 1)In the metal ratchet,the movement direction of particles is reversal,and the movement speed of particles in the saw channel changes periodically.When the pressure or power is changed,the change of sheath causes the average angular velocity of particles to decrease with the increase of power or pressure.Furthermore,we study the experimental process numerically and reproduce the experimental phenomenon.2)The evolution process of particle distribution in the metal ring gear,from dust cloud to dust chain,is very similar to that in the resin ring gear.The difference is that the dust vortex in the metal ring gear has the phenomenon of positive and negative rotation,which is reversible and controllable.The mechanism of the reversal of the rotating direction of the dust vortex is the same as that of the particles in the dust plasma ratchet.It also stems from the reversal of the potential energy of the asymmetric ratchet along the tangential direction under different plasma parameters.3)Compared with the dense material dust particles and polar medium dust particles,resin ratchet has better rectification effect on porous material dust particles and non-polar medium particles.The results further improve the dust plasma ratchet model,get a more comprehensive mechanism and law of the realization of the rectification of dust plasma ratchet,and help to understand the dynamics mechanism of dust particles in the plasma.On this basis,the scheme of dusty plasma motor can be further designed and improved to realize the utilization of dust particle energy in plasma environment.