Electron temperature measurements using a 12-channel array probe

The electron temperature in a pulsed high-β ( β≡2μnkT/B2≊1) plasma is studied as a function of time using a miniature array of 12 planar Langmuir probes. Instead of sweeping the bias voltage on the collectors, each is set at a different voltage corresponding to points along the characteristic I–V curve. A fast-analog multiplexer, together with a computerized data-acquisition system, allows determination of Te to within a few percent accuracy, with a time resolution of 1 μs. The probe is used to study temperature fluctuations and heat transport in a plasma current sheet.