Title: Ion beam neutralization and properties of plasmas from low power ring cusp ion thrusters Available
Authors: E. Criado, E. Roibás, S. P. Tierno, P. Rodríguez De Francisco, J. L. Domenech-Garret, J. M. Donoso, L. Conde
Date of publication: February 15th 2012
Journal: Physics of Plasmas
DOI: https://doi.org/10.1063/1.3684229
Abstract: The design and operation modes of a small, low power ion plasma thruster and the properties of the emitted plasma plumes are discussed. The ion beam is extracted from a primary plasma produced by a stationary low pressure electric discharge where the ion production rate is essentially determined by the discharge current. The experiments evidence that the electron neutralization current controls the space charge levels of the outgoing ion current and also influences the spatial properties of emitted plasmas. The electron plasma density increases with the discharge and the electron neutralization currents, while decreases as the plasma plume expands. However, the corresponding electron temperatures decrease when the electron neutralization currents increments. The collisional origin of this electron cooling effect is excluded because of the large collisional mean free paths involved. Then, these electron energy losses during the neutralization of the ion beam would be caused by more subtle physical mechanisms than collisions. The experimental results are compared with previous numerical simulations and similar phenomena found in other experiments.