Structure of the plasma-wall interaction in an oblique magnetic field
- E.T.S.I. Aeronauticos, Departamento de Fundamentos Matematicos, Universidad Politecnica, 28040 Madrid (Spain)
The influence of the magnetic field strength B and angle of incidence {psi} on the one-dimensional (1-D) structure of a weakly collisional plasma near a charged wall is investigated. The models of Chodura [Phys. Fluids {bold 25}, 1628 (1982)] and Riemann [Phys. Plasmas {bold 1}, 552 (1994)] are recovered as particular cases: intermediate-B and weak-B cases, respectively, of the model presented here, and are compared with a third, strong-B case, where the space-charge sheath is partially magnetized. A triple structure comprising (collisional) presheath, Chodura layer, and sheath, exists only for the intermediate-B case. For weaker and stronger ranges of B, the Chodura layer disappears immersed into the presheath and the sheath, respectively, recovering a classical double-structure. In the Chodura model the importance of the collisional presheath to characterize completely the perturbation region is discussed. For the weak-B case: results for the whole range of angles of incidence are presented and compared; for grazing incidence and a near-collisionless plasma, an approximate analytical solution is derived; and, the asymptotic convergence to the triple-structure is shown. For the strong-B case, the analysis includes: (i) an involved derivation of the local behavior around the entrance point to the sheath, and (ii), for a certain range of {psi}, to cross, with a regular solution, an internal singular point of the sheath equations. The similarities between the entrance conditions to the different plasma regions are pointed out. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 553023
- Journal Information:
- Physics of Plasmas, Vol. 4, Issue 12; Other Information: PBD: Dec 1997
- Country of Publication:
- United States
- Language:
- English
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