Large, quiescent, magnetized plasma for wave studies

Abstract

The development of a large magnetized plasma source for wave propagation experiments is described. The method employs a dc discharge in a weak magnetic field region and subsequent particle diffusion into a strong, uniform B‐field region. The resultant steady‐state plasma is uniform (8 cm⊥B₀, 120 cm∥B₀), quiescent (δn/n≲1%), has high density (n_e≳10¹¹ cm⁻³), a B₀=1 kG, argon (3×10⁻⁴ Torr), and low collision rates (ν_en≃10⁵ sec⁻¹). The source can be easily scaled to larger dimensions. Plasma diagnostics with probes, microwaves, and spectroscopy for steady state and afterglow are described. Examples of wave propagation for ion acoustic waves, electron Bernstein waves, and lower hybrid waves indicate the versatility of the device.