Measurement of Low Plasma Densities in a Magnetic Field

摘要: Absolute measurements of plasma density in the range 8× 108 to 3× 1011cm−3 were made a potassium by four methods: (1) Langmuir probes, (2) microwave cavity, (3) interferometry, and (4) propagation electrostatic waves. Agreement ≈25% between probe was achieved careful application theory. By contrast, indiscriminate use theory would lead an error 600% at low densities. The fourth method, though less accurate, found be useful independent check.