Model experiments to study the first wall erosion by vacuum arcs

Unipolar arcs acting on the first wall of future thermonuclear reactors were modelled by bipolar arcs burning on the side surface of a cylindrical titanium cathode. Erosion rate and spatial distribution of the material sputtered in arcs were investigated by Rutherford Backscattering (RBS) analysis of collector probes. The obtained results will be discussed as a function of arc current and the intensity of the applied vault-shaped magnetic field.