Two-dimensional plasma expansion in a magnetic nozzle: Separation due to electron inertia

Journal Article · Wed Aug 15 04:00:00 EDT 2012 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4739791· OSTI ID:22086080

Ahedo, Eduardo; Merino, Mario ^[1]

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1. Universidad Politecnica de Madrid, 28040 Madrid (Spain)

A previous axisymmetric model of the supersonic expansion of a collisionless, hot plasma in a divergent magnetic nozzle is extended here in order to include electron-inertia effects. Up to dominant order on all components of the electron velocity, electron momentum equations still reduce to three conservation laws. Electron inertia leads to outward electron separation from the magnetic streamtubes. The progressive plasma filling of the adjacent vacuum region is consistent with electron-inertia being part of finite electron Larmor radius effects, which increase downstream and eventually demagnetize the plasma. Current ambipolarity is not fulfilled and ion separation can be either outwards or inwards of magnetic streamtubes, depending on their magnetization. Electron separation penalizes slightly the plume efficiency and is larger for plasma beams injected with large pressure gradients. An alternative nonzero electron-inertia model [E. Hooper, J. Propul. Power 9, 757 (1993)] based on cold plasmas and current ambipolarity, which predicts inwards electron separation, is discussed critically. A possible competition of the gyroviscous force with electron-inertia effects is commented briefly.

• OSTI ID: 22086080
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 8 Vol. 19; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
AXIAL SYMMETRY
COLD PLASMA
COLLISIONLESS PLASMA
CONSERVATION LAWS
ELECTRIC CURRENTS
ELECTRONS
HOT PLASMA
IONS
LARMOR RADIUS
MAGNETIZATION
MOMENT OF INERTIA
MOMENTS METHOD
NOZZLES
PLASMA BEAM INJECTION
PLASMA EXPANSION
PRESSURE GRADIENTS
SUPERSONIC FLOW
TWO-DIMENSIONAL CALCULATIONS