The project “Plasmakristall – 4” (PK–4) is a dusty plasma experiment in a combined dc/rf(i) discharge plasma under microgravity conditions

During the last decade decade there has been a continually growing interest to the complex dusty plasma physics [1], [2]. A dusty plasma is a low temperature plasma with immersed dust grains of micrometer size. These grains are quickly charged under plasma exposition and become by a component of the plasma. The main features of this component are the very large and variable electric charge (up to 10 of electron charges) and the large mass of the grains. This leads to qualitatively new physical phenomena in plasmas space ordering of the dust component, wide spectrum of specific kinds of dust instabilities, very low frequency (∼ 10 Hz) dust acoustic waves, etc [3], [4]. In addition to the fundamental interest, the complex plasma is a unique physical object allowing to model and investigate different physical phenomena from other fields of physics on the kinetic and microscopic level phase transitions, crystal shift deformations, shock waves and solitons, laminar and turbulent flow of highly nonideal liquid and so forth. As a rule, the Earth gravity exerts an external stress on the dust component in laboratory experiments. To avoid this stress during some period, the experiments should be performed under microgravity conditions. Microgravity conditions can be achieved by using falling platforms, rockets, parabolic flights in air planes, or orbital flights. The PK-4 experiment [5] is a continuation of the successful dusty