Erik I. Asinovskii

Dust structures in cryogenic gas discharges

Results are given of experimental investigations of dust structures of monodisperse particles in a low-pressure dc glow discharge at temperatures of liquid nitrogen ( T = 77 K ) and liquid helium ( T = 4.2 K ) . It is found that the cooling of discharge at invariant discharge current and neutral gas density causes a decrease in the interparticle spacing in structures and an increase in the kinetic energy of dust particles. The forming of a superdense dust structure with free boundaries is observed for the first time at 4.2 K .

Dusty Plasma Structures in Cryogenic DC Discharges

Experimental investigations of dust structures in dc low‐pressure glow discharge at temperatures of liquid nitrogen (T = 77 K) and liquid helium (T = 4.2 K) are presented. Super dense dust structures with dust density np ∼ 108–109 cm−3 formed within striations of cryogenic discharges as well as boundary‐free worm‐like dust structure moved in discharge at 4.2 K were obtained.

Evolution of Dust Structures from Room to Cryogenic Temperatures

In this work dusty plasma of dc glow discharge at the temperatures in the range of 4.2–300 K was experimentally and numerically investigated. As it was shown in the experiments, the deep cooling of discharge tube walls leads to dramatic change of dusty plasma properties. In particular, sufficient increase of dust particle kinetic temperature (by about an order) and dust density (by several orders) was observed at low (cryogenic) temperatures. At 4.2 K, this can lead to the forming of a super dense dust structures with novel properties. Numerical simulations of charging process, dust charge fluctuation and screening of dust particle charge in plasma were made in dependence with the neutral gas temperature and dust density. The main attention was given to proper ion‐atom collision analysis that allows us to investigate mechanisms of dust structure transformation observed in the cryogenic experiments.