Joint Institute for High Temperatures RAS, Moscow, Russia
Moscow Institute of Physics and Technology, Dolgoprudny, Russia
Charged Dust in Laboratory and Space: from Chaos to Ordering and Back
The charged dust represent a non-neutral or quasi-neutral systems (dusty plasmas) containing micron-sized particles (dust or grains) of a substance with electrical charges up to 102-105e. As a result of strong interaction of the strongly charged dust particles they may form the ordered structures of liquid and crystal types that are different from gas-like or chaotic systems. Most of the laboratory studies of dusty plasmas are carried out in weakly ionized gas discharge plasmas. As a result, the laboratory dusty plasma is the unique object for studying the structure, phase transitions and transport properties of the systems of interacting grains on the “kinetic level”. Dust system is affected by gravity, depending on the size of the solid particles gravity can be the dominating force. Under microgravity conditions in space much weaker forces become important and other new phenomena not achievable on Earth can be observed. In this report results are presented from the experimental studies of charged dust systems under ground bounded and microgravity conditions. Structural and transport characteristics of dust in plasmas were measured in a set of experiments in rf gas-discharge plasmas in microgravity conditions onboard of International Space Station. The formation of ordered structures from large number (~104) of charged diamagnetic dust particles in a cusp magnetic trap under microgravity conditions has been studied. Dusty plasmas were also investigated in a combined dc/rf discharge under microgravity conditions in parabolic flights. The numerical simulations of the lunar plasma-dust exosphere caused by action of solar ultraviolet radiation and the incoming solar wind on the lunar surface have been carried out. The influence of the solar wind flux on the near-surface photoelectron sheath formation as well as conditions of dust levitation above the lunar surface have been analyzed. The phase transitions in quasi-two-dimensional dust structures suspended in rf discharge were studied in experiments. The results reveal the existence of hexatic phase as well as solid-to-hexatic phase and hexatic-to-liquid transitions.