Large quiescent collisionless high-frequency discharge plasma

200 V p‐p (peak to peak) at 80 MHz applied to a plane sheet electrode of 0.0075‐cm‐diam parallel wires produces a reasonably uniform large‐volume collisionless plasma in zero magnetic field with a density of ∼ 10⁹ ions/cm³ in argon at 3 × 10⁻⁴ Torr. The noise fluctuation level ${\text{〈δn/n〉 ≃ 2 × 10}}^{\text{−4}}$ .