Bohm criterion and plasma particle/power exhaust to and recycling at the wall
The plasma particle and power exhaust to the divertor surface drives both particle and power recycling at the surface, which in return constrains the plasma density and temperature at the target and their profile further upstream. Both particle and power exhaust fluxes are mediated by the plasma sheath next to the divertor surface. In particular, the Bohm criterion constrains the ion exit flow speed, which enters directly into the particle flux and the kinetic flow energy component of the ion power flux, and indirectly into the electron power flux through the sheath potential drop. Here we give an overview on how the Bohm speed is set in a general plasma and how it enters power exhaust and power recycling at the divertor surface, and the implication on the correct implementation of sheath boundary conditions in numerical codes. The cases of ideal and non-ideal Bohm speed are distinguished as a result of the physics discussion.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR); USDOE Office of Science (SC). Advanced Scientific Computing Research (ASCR) (SC-21); USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Grant/Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1361705
- Alternate ID(s):
- OSTI ID: 1369183
- Report Number(s):
- LA-UR-16-24857; S2352179116302307; PII: S2352179116302307
- Journal Information:
- Nuclear Materials and Energy, Journal Name: Nuclear Materials and Energy Vol. 12 Journal Issue: C; ISSN 2352-1791
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
Web of Science
Similar Records
Bohm Criterion of Plasma Sheaths away from Asymptotic Limits
The Bohm--Chodura plasma sheath criterion