Magnetic Multipole Containment of Large Uniform Collisionless Quiescent Plasmas

Abstract

Over 1200 Alnico magnets (1.3 × 1.3 × 4 cm) are used to contain a conventional discharge plasma produced by 1–20 A of emission from 6–48 small filaments at − 60 V. Densities up to 10¹² ions/cm³ are produced in argon at 2 × 10⁻³ Torr. At 5 × 10⁻⁶ Torr typical parameters are: 8 × 10¹⁰ ions/cm³; n_i / n₀ ≈ 0.7; T_e ≈ 5 eV; T_i ≈ 0.5 eV; noise 〈 δn/n 〉 ≈ 2 × 10⁻⁴; and < 1% nonuniformity over a volume 31 cm diam by 69 cm. Uniform dense plasmas of He, D, and H are also produced. The ion containment appears to be both magnetic and electrostatic.