Fundamental processes of dust particles under plasma conditions in low-temperature laboratory experiments and fusion devices

Fundamental processes of dust particles in low-temperature laboratory plasmas are summarized, particularly focusing on charging dynamics, in which the importance of electron energy distribution function is stressed. A delayed charging from local equilibrium charge may provide the energy to dust particles due to electrostatic field in the sheath, which may be the origin of spontaneously excited vertical oscillation. The dispersion relation for vertically polarized dust lattice wave is formulated, taking such a charging dynamics into account. Such dust waves excited externally as well as spontaneously are demonstrated experimentally. Recent observations show a great amount of dust near the divertor region in magnetic fusion devices. Role of dust in fusion devices are discussed in terms of tritium retention and safety. Some mechanisms for dust formation in fusion environment are suggested. (author)