Remarks on the use of deposition probes for analysis of tokamak boundary-layer plasmas

The deposition of impurities and plasma ions on probes exposed in plasma devices can be used as a diagnostic method for characterizing boundary-layer plasmas. Recent tokamak experiments have shown that quantitative measurements of impurity and plasma particle profiles can be obtained from ion scattering and nuclear reaction analysis of samples exposed in the plasma edge. For such measurements to become meaningful diagnostics, they must be related to the plasma edge behavior. In the present work a simple analytic model of the boundary-layer plasma is utilized to explore the relationship between the deposition profile on such probes and the particle confinement time and ionization probability of wall-originated impurities in the boundary layer