Simulations of carbon sputtering in amorphous hydrogenated samples

J. MARIAN; L.A. ZEPEDA-RUIZ; G. GILMER; E. BRINGA; T. ROGNLIEN

PHYSICA SCRIPTA - (Print)

IOP PUBLISHING LTD

Año: 2006 vol. 2006 p. 65 - 69

0031-8949

The interaction of edge plasma with material surfaces raises key issues for the viability of the international thermonuclear reactor (ITER) and future fusion reactors, including heat-flux limits, net material erosion and impurity production. After exposure of the graphite divertor plates to the plasma in a fusion device, an amorphous C/H layer forms. This layer contains 20–30 atomic percent D/T bonded to C. Subsequent D/T impingement on this layer produces a variety of hydrocarbons that are sputtered back into the sheath region. We present molecular dynamics (MD) simulations of D/T impacts on amorphous carbon layer as a function of ion energy and orientation, using the AIREBO potential. In particular, energies are varied between 10 and 150 eV to transition from chemical to physical sputtering. These results are used to quantify yield, hydrocarbon composition and eventual plasma contamination.