11 research outputs found
Dissipative solitary wave at the interface of a binary complex plasma
The propagation of a dissipative solitary wave across an interface is studied
in a binary complex plasma. The experiments were performed under microgravity
conditions in the PK-3 Plus Laboratory on board the International Space Station
using microparticles with diameters of 1.55 micrometre and 2.55 micrometre
immersed in a low-temperature plasma. The solitary wave was excited at the edge
of a particle-free region and propagated from the sub-cloud of small particles
into that of big particles. The interfacial effect was observed by measuring
the deceleration of particles in the wave crest. The results are compared with
a Langevin dynamics simulation, where the waves were excited by a gentle push
on the edge of the sub-cloud of small particles. Reflection of the wave at the
interface is induced by increasing the strength of the push. By tuning the ion
drag force exerted on big particles in the simulation, the effective width of
the interface is adjusted. We show that the strength of reflection increases
with narrower interfaces
Density waves at the interface of a binary complex plasma
Density waves were studied in a phase-separated binary complex plasma under microgravity conditions. For the big particles, waves were self-excited by the two-stream instability, while for small particles, they were excited by heartbeat instability with the presence of reversed propagating pulses of a different frequency. By studying the dynamics of wave crests at the interface, we recognize a “collision zone” and a “merger zone” before and after the interface, respectively. The results provide a generic picture of wave-wave interaction at the interface between two “mediums”
PKE–Nefedov*: plasma crystal experiments on the International Space Station
Abstract. The plasma crystal experiment PKE–Nefedov, the first basic science experiment on the International Space Station (ISS), was installed in February 2001 by the first permanent crew. It is designed for long-term investigations of complex plasmas under microgravity conditions. ‘Complex plasmas ’ contain ions, electrons, neutrals and small solid particles—normally in the micrometre range. These microparticles obtain thousands of elementary charges and interact with each other via a ‘screened ’ Coulomb potential. Complex plasmas are of special interest, because they can form liquid and crystalline states (Thoma