Argonne National Laboratory

Sheath Parameters for Non-Debye Plasmas: Simulations and Arc Damage

TitleSheath Parameters for Non-Debye Plasmas: Simulations and Arc Damage
Publication TypeJournal Article
Year of Publication2011
AuthorsMorozov, I, Norman, GE, Insepov, Z, Norem, J
Date Published09/2011
Other NumbersANL/MCS-P1954-0911

In this paper we report results for MD simulations of the dense, nonideal plasma sheath near a metallic surface. We use Molecular Dynamics (MD) to evaluate sheaths in the nonDebye region for high density, low temperature plasmas. We use direct two-component MD simulations where the interactions between all electrons and ions are computed explicitly. Although MD simulations have limited space and time scales their results can be considered as the lower level output for the multiscale approach. We find that the nonDebye sheath can be extrapolated from the Debye sheath parameters with small corrections. Using these results, and equating surface tension and plasma pressure, it is possible to infer a range of plasma densities and sheath potentials from SEM images of arc damage. We find that these parameters are consistent with previous PIC code estimates, pointing to densities in the range 10^24 - 10^25/m3. The sub-micron component of arc damage can be both: a) the most direct indicator the internal parameters of the arc plasma, and b) the most likely cause of further breakdown events due to high enhancement factors.