Dust in fusion devices - experimental evidence, possible sources and consequences

Dust can play an important role in fusion devices. Various mechanisms for dust production are discussed including the possible growth of particulates during the fusion plasma discharge itself. Samples of dust from TEXTOR-94 are analysed by scanning electron microscopy. The particle size ranges from millimetres down to < 100 nm. The morphology of the smallest particles suggests their plasma-induced growth. Part of the dust is ferromagnetic. The impact of dust particles on safety, plasma operations and performance is addressed.