Redeposition of hydrocarbon layers in fusion devices

Co-deposition of hydrogen isotopes with carbon in nuclear fusion experiments is a topic of paramount importance for a next-step device. Physical sputtering, chemical erosion, and chemical sputtering of carbon by hydrogen isotopes lead to release of hydrocarbon species which are transported to plasma shaded regions and lead there to deposition of co-deposited layers. Co-deposition is generally believed to be the dominant tritium retention mechanism in a next-step device. The article reviews recent experimental results regarding co-deposition in fusion devices, and basic low-temperature plasma and particle-beam experiments relevant to co-deposition of hydrocarbon layers in nuclear fusion devices.