Electron-Ion Beam Coupling Through Collective Interactions
AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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Neutralization of ion beams in electric propulsion applications is a well-known phenomenon. The physics behind the robust matching of both ion and electron currents and densities are not. With electric propulsion devices moving into micro and macro regimes with colloids, FEEPs, and thruster arrays, thruster-neutralizer interactions are under increasing scrutiny. It is shown that Coulomb collisions, which can act to match velocities through strong ion-electron collisions between particles with low relative velocities, are far too slow to explain the phenomenon. Further examination of the strong beam-plasma, or Buneman, instability yields a candidate for the neutralization mechanism. Differences in simulations from analytic theory are discussed.
- Particle Accelerators
- Plasma Physics and Magnetohydrodynamics
- Electric and Ion Propulsion