TRAPPING OF ENERGETIC IONS BY NEUTRALIZATION OF A POLARIZED BEAM

Recent experiments show that a positive ion beam with a density exceeding 10/sup 8/ ions/cm/sup 3/ will neutralize its space charge by trapping electrons within the beam. This trapping of electrons converts the ion beam to a neutral plasma suitable for injection and polarization experiments in a cross magnetic field. The ion energy used is about 500 volts. The beam moves readily across the magnetic field due to polarization of positive and negative charges. To create a hot plasma, it will be necessary to use higher energy ions, increase beam density, and retain neutralization by trapped electrons. (W.L.H.