Operation of a 0.2–1.1 keV ion source within a magnetized laboratory plasma

To study the physics of energetic ions in magnetized plasma, a rf ion beam is inserted into the 1 kG, ∼3 eV, ∼1012 cm−3 plasma produced by the upgraded LArge Plasma Device (LAPD). The commercial 100–1000 eV argon source normally operates in an unmagnetized microelectronics production environment. Successful operation in the LAPD requires numerous modifications, including electrical isolation of the source housing, relocation of the matching network for the rf, reduction of the gas pressure, pulsed operation to avoid overheating, and care to preserve current neutralization in the presence of a strong magnetic field. With these modifications, a ∼500 eV, milliampere beam that propagates axially more than 6 m is obtained.