Abstract
In many plasma devices, steel or inconel walls are exposed to large flux densities phi/sub 1/ of atomic hydrogen particles which, soon after the reduction of the surface oxides and carbides has started, penetrate into the lattice. The stationary hydrogen concentration c/sub 1/ in the lattice is expressed as function of phi/sub 1/, of the wall temperature Tsub(w) and of the surface roughness factor sigma. It is found to be much larger than in an H/sub 2/ surrounding. Dissolved atoms recombining on internal surfaces (i.e. at grain boundaries) within the solid can then build up a considerable pressure Psup(p)sub(H/sub 2/) within resulting gas pockets; Psup(p)sub(H/sub 2/) should depend strongly on Tsub(w). Near room temperature, the computed values are such that surface-near pockets should crack open, releasing locally high pressure H/sub 2/ gas and some metal dust (impurity source) and increasing sigma. The expected distribution of csub(H) within the sponge-like structure which is expected to result from a prolonged exposure to phi/sub 1/ at low Tsub(w) is derived. Means of avoiding the plasma contamination by dust release are pointed out.
Khan, I A;
Dietz, K J;
Waelbroeck, F;
Wienhold, P
[1]
- Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Plasmaphysik
Citation Formats
Khan, I A, Dietz, K J, Waelbroeck, F, and Wienhold, P.
Plasma cooling by metal snow. I. Origin of the effect and elimination procedures.
Netherlands: N. p.,
1978.
Web.
doi:10.1016/0022-3115(78)90541-X.
Khan, I A, Dietz, K J, Waelbroeck, F, & Wienhold, P.
Plasma cooling by metal snow. I. Origin of the effect and elimination procedures.
Netherlands.
https://doi.org/10.1016/0022-3115(78)90541-X
Khan, I A, Dietz, K J, Waelbroeck, F, and Wienhold, P.
1978.
"Plasma cooling by metal snow. I. Origin of the effect and elimination procedures."
Netherlands.
https://doi.org/10.1016/0022-3115(78)90541-X.
@misc{etde_6380187,
title = {Plasma cooling by metal snow. I. Origin of the effect and elimination procedures}
author = {Khan, I A, Dietz, K J, Waelbroeck, F, and Wienhold, P}
abstractNote = {In many plasma devices, steel or inconel walls are exposed to large flux densities phi/sub 1/ of atomic hydrogen particles which, soon after the reduction of the surface oxides and carbides has started, penetrate into the lattice. The stationary hydrogen concentration c/sub 1/ in the lattice is expressed as function of phi/sub 1/, of the wall temperature Tsub(w) and of the surface roughness factor sigma. It is found to be much larger than in an H/sub 2/ surrounding. Dissolved atoms recombining on internal surfaces (i.e. at grain boundaries) within the solid can then build up a considerable pressure Psup(p)sub(H/sub 2/) within resulting gas pockets; Psup(p)sub(H/sub 2/) should depend strongly on Tsub(w). Near room temperature, the computed values are such that surface-near pockets should crack open, releasing locally high pressure H/sub 2/ gas and some metal dust (impurity source) and increasing sigma. The expected distribution of csub(H) within the sponge-like structure which is expected to result from a prolonged exposure to phi/sub 1/ at low Tsub(w) is derived. Means of avoiding the plasma contamination by dust release are pointed out.}
doi = {10.1016/0022-3115(78)90541-X}
journal = []
volume = {74:1}
journal type = {AC}
place = {Netherlands}
year = {1978}
month = {Jun}
}
title = {Plasma cooling by metal snow. I. Origin of the effect and elimination procedures}
author = {Khan, I A, Dietz, K J, Waelbroeck, F, and Wienhold, P}
abstractNote = {In many plasma devices, steel or inconel walls are exposed to large flux densities phi/sub 1/ of atomic hydrogen particles which, soon after the reduction of the surface oxides and carbides has started, penetrate into the lattice. The stationary hydrogen concentration c/sub 1/ in the lattice is expressed as function of phi/sub 1/, of the wall temperature Tsub(w) and of the surface roughness factor sigma. It is found to be much larger than in an H/sub 2/ surrounding. Dissolved atoms recombining on internal surfaces (i.e. at grain boundaries) within the solid can then build up a considerable pressure Psup(p)sub(H/sub 2/) within resulting gas pockets; Psup(p)sub(H/sub 2/) should depend strongly on Tsub(w). Near room temperature, the computed values are such that surface-near pockets should crack open, releasing locally high pressure H/sub 2/ gas and some metal dust (impurity source) and increasing sigma. The expected distribution of csub(H) within the sponge-like structure which is expected to result from a prolonged exposure to phi/sub 1/ at low Tsub(w) is derived. Means of avoiding the plasma contamination by dust release are pointed out.}
doi = {10.1016/0022-3115(78)90541-X}
journal = []
volume = {74:1}
journal type = {AC}
place = {Netherlands}
year = {1978}
month = {Jun}
}