Interaction of a supersonic particle with a three-dimensional complex plasma

Abstract

The influence of a supersonic projectile on a three-dimensional complex plasma is studied. Micron sized particles in a low-temperature plasma formed a large undisturbed system in the new "Zyflex" chamber during microgravity conditions. A supersonic probe particle excited a Mach cone with Mach number M ≈ 1.5 − 2 and double Mach cone structure in the large weakly damped particle cloud. The speed of sound is measured with different methods and particle charge estimations are compared to calculations from standard theories. The high image resolution enables the study of Mach cones in microgravity on the single particle level of a three-dimensional complex plasma and gives insight to the dynamics. A heating of the microparticles is discovered behind the supersonic projectile but not in the flanks of the Mach cone.

Pressure- and Size-Dependent Aerodynamic Drag Effects on Mach 0.3–2.2 Microspheres for High-Precision Micro-Ballistic Characterization

“…In the supersonic regime, C D increases with decreasing M. Figure 3b illustrates how pressure drag mainly contributes to drag force in this regime due to the large low-pressure region in the wake of the detached bow shock, which contains a toroidal recirculation region downstream of the sphere [22,23]. As the supersonic velocity decreases, the angle of the shock wave increases, causing the low-pressure region in its wake to expand [23,24]. Expansion of the low-pressure region incurs greater pressure drag and results in an increase in C D .…”

Image Registration with Particles, Examplified with the Complex Plasma Laboratory PK-4 on Board the International Space Station

“…Then, we counted the number of magenta pixels belonging to particles in the overlap region, n mp , in both time series Method I: n mp = 80844 (16) Method II: n mp = 84633.…”

“…Under microgravity conditions, however, the microparticles are suspended in the bulk of the discharge, where the conditions are more favorable for studying undisturbed systems. This allows, for instance, investigations of velocity distributions [ 14 ], Mach cones [ 15 , 16 ], turbulence [ 17 ], waves [ 18 , 19 , 20 , 21 , 22 ], lane formation [ 23 ], electrorheological plasmas [ 22 ], demixing [ 22 , 24 ], particle charging [ 25 ], and crystallization [ 10 , 26 ].…”

Penetration of a supersonic particle at the interface in a binary complex plasma

“…Under * chengran.du@dhu.edu.cn microgravity conditions, the particles form a relatively homogeneous 3D complex plasma. The penetration of the extra particles results in a moving disturbance inside the particle cloud, generating a 3D Mach cone if moving faster than the speed of sound [32,37,39,40].…”