Physics of Plasmas · 2001 · 150 citations · 9 references
Natural SciencesAerospace EngineeringPhysicsFluid DynamicsPlasma PhysicsPropulsionHall Effect ThrustersMagnetized PlasmaPlasma Kinetic TheoryPlasma SheathsPlasma SimulationPlasma TransportAcceleration PerformanceIon FlowIon ThrustersIonizationIonization DynamicsPlasma ExpansionPlasma ThrustersThruster Performance Modeling
The one‑dimensional steady plasma flow in a Hall thruster consists of an anode sheath, a long electron‑free diffusion region with reverse ion flow, a thin ionization layer, and an acceleration region extending into the plume, with the ion flow reaching a forward sonic point either internally or at the channel exit. The study presents a macroscopic model that captures electrostatic, thermal, and kinetic interactions in a Hall thruster. The model incorporates a simple expansion representation of the supersonic plume to close the equations and compute thruster performance. The model agrees well with experiments for an internal sonic point, maps parameter regions of existence versus nonexistence, and shows that electron pressure, reverse ion flow, and ionization rate dominate the plasma structure while the magnetic field profile has only a weak effect.
A macroscopic model which accounts for the complex interactions between electrostatic, thermal, and kinetic effects in a Hall thruster is presented. The analysis establishes the one-dimensional steady structure of the flow as consisting of an anode sheath, a long electron free-diffusion region, with reverse ion flow, a thin ionization layer, and the acceleration region, which extends into the plume. The ion flow presents a forward sonic point around the exit of the ionization layer, which can be either internal, with a smooth sonic transition, or localized at the channel exit. The supersonic plume is included via a simple expansion model, allowing closure of the formulation and calculation of thruster performance. The results indicate good agreement with experimental data for the case of an internal sonic point, and they delineate the existence and nonexistence regions in the space of externally controllable parameters. They also unveil the importance of the electron pressure, the reverse flow of ions, and the ionization rate in shaping the plasma structure, whereas, contrary to common perception, the details of the magnetic field profile influence weakly that structure.
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