マイクロ波反射法による高密度プラズマの測定 (I)

概要

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A new method for measuring high density plasma has been proposed by one of the authors, the principle of this method being that the electron density and the collision freouency can be determined simultaneously from a complex reflection coefficient at a plane boundary of a high density plasma. The complex reflection coefficient can be obtained from the amplitudes of two standing wave signals measured at different Dositions separated each other by a quater of the wave length. This method is here extended : very simple expressions relating the electron density and the collision frequency to the standing wave signals are deduced. Some improvement by which experimental errors will be reduced are introduced, and also a treatment is given of a case where some fractions of incident and reflected powers are discipated or scattered. along the path between the plasma boundary and the detectors. Reflection and transmission coefficients for a planar plasma of finite thickness are calculated, showing that a. kind of resonance appears due to multiple reflection at both boundaries of the plasma layer when the electron density approaches to the plasma frequency. By applying the method to a shock-produced plasma, an electron density up to the order of 1016 cm -3 is measured with a x-band microwave.
社団法人プラズマ・核融合学会の論文