Dust-surface collisions in adhesion regime for tokamak relevant materials

Empirical studies of dust-surface collisions for metal and carbon projectiles impacting on metal targets in the velocity range from a few m/s to those in excess of 1 km/s have been carried out with the use of a modified pellet injection system. The selected projectile/target shapes, sizes and materials are mimicking the scenario of dust colliding with plasma facing components (PFCs) of a metal machine. The low velocities (10's m/s) reported here, characteristic for dust motion in tokamak scrape-off layer plasmas, are in the range of sticking phenomenon; the critical velocity and size for bouncing off are essential and timely inputs for the dust dynamics codes and statistical models aiming to predict dust transport and redeposition on PFCs. © 2013 Elsevier B.V. All rights reserved.