我們設計一個使用範圍在我們磁化電漿實驗操作範圍內的低頻螺旋電漿源系統。這個超低頻螺旋電漿源可以延伸應用微擾量測實驗的頻率。為了未來的高功率系統此裝置基於預算或是訓練目的完全是可以在家製造的。此系統包含了功率放大器，功率量測系統，匹配器與天線。我們測試此系統的整體效能與特性並確認它符合我們的需求。它最大可以發出20W的功率。
我們計算均勻與非均勻電漿密度的螺旋波分布關係。同時我們利用功率平衡關係式來估計需求功率。這些結果都將運用於設計我們的螺旋電漿源。
低頻螺旋系統應用在磁化電漿實驗的數據指出利用入射的射頻波可以增加電子密度。此結果是利用光譜量測氬氣放射光譜的結果。同時我們也嘗試利用精密尺度的磁力拾波線圈來測量波的結構。比較實驗結果和計算的分布關係指出我們所觀察到的密度增長並非螺旋波而是電感耦合電漿模式。所以也許我們需要高功率系統(>900W)激發螺旋波。

We developed a low frequency (~100 kHz) helicon source system in order to expand operating space of magnetized plasma experiment (MPX). This extreme low frequency helicon source may have unique aspects such as possibility of application to high frequency fluctuation (MHz range) measurement experiment. This development was implemented completely in-house because of financial reason and training purpose for future introduction of high power system. The helicon system consists of a power amplifier, a power measurement system, a matching circuit and an antenna. Its integrated performance was tested and we confirmed the helicon system satisfies our requirement. The system has output power of 20 W at maximum.
We calculated dispersion relation of helicon wave for cases of uniform plasma density and nonuniform plasma density by following F. F. Chen’s work [Francis F. Chen 1993 Plasma Sources Sci. Technol. 3 49-57]. Also we estimated required power from a simple power balance equation. Results were used for the design of our helicon source system.
Experimental result of application of the low frequency helicon system to MPX indicated increase in electron density by injection of the rf wave. This increase was measured by a spectroscopic measurement of neutral argon emission. Also we attempted to measure wave field structure by using a fine scale pick-up coil array. Comparison between experiment and calculation of the dispersion relation implies that observed density increase was induced by other mechanisms rather than excitation of helicon mode such as ICP mode. A high power system (>900W) may be needed for excitation of helicon wave.

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