Solitary wave pulse in structure of charged microparticles
The paper presents the experimental and theoretical study on wave processes in the structures of charged microparticles without Debye screening. For experimental study the setup that contained a module for particle charging and a module for particle capturing was assembled. In experiments the aluminum oxide particles were used. They were injected into the module for particle charging where under the influence of gravity they passed through the corona discharge region getting positive charge. Thereafter, the particles were deposited into the trap Paul, where they were captured and formed the Coulomb structures of elongated shape. To prevent particle flowing out from the ends of the trap at one end the ring electrode was installed at which constant electric potential was applied. At another end (free end) of the trap particles were held by effective force, the so-called Gaponova-Miller force, arising as a result of the electric field alterations. At this free end self-excitation of the solitary wave took place, the wave moved along the structure without any decay. When approaching the end of the trap with ring electrode of free end the wave reflected and moved in the opposite direction at the same speed. Wave velocity has been experimentally determined. Besides, the wave speed was theoretically estimated under next assumptions: the coulomb structure was considered as a continuous medium, viscous forces were not included in the calculation, the density of the structure over its entire length was constant and wave velocity coincided with the speed of sound. Theoretically estimated wave velocity qualitatively coincided with the experimental results.