Double layers (DLs) have been observed in a plasma reactor composed of a source chamber attached to a larger expanding chamber. Positive ion beams generated across the DL were characterized in the low plasma potential region using retarding field energy analyzers. In electropositive gases, DLs were formed at very low pressures between 0.1 and 1 mTorr with the plasma expansion forced by a strongly diverging magnetic field. The DL remains static, robust to changes in boundary conditions, and its position is related to the magnetic field lines. The voltage drop across the DL increases with decreasing pressure, i.e., with increasing electron temperature around 20 V at 0.17 mTorr. DLs were also observed in electronegative gases without a magnetic field over a greater range of pressure 0.5 to 10 mTorr. The actual profile of the electronegative DL is very sensitive to external parameters and intrusive elements, and they propagate at high negative ion fraction. Electrostatic probes measurements and laser-induced photodetachment show discontinuities in all plasma parameters electron density, electron temperature, negative ion fraction at the DL position. The voltage drop across the electronegative DL is about 8 V, is independent of the gas pressure and therefore of the electron temperature.
翻译:在由较扩大的室中附属的源舱组成的等离子反应堆中观测到了双层(DLs),该等离子反应器由较大型的室室组成。在低等离子潜在区域中,使用缓缓冲场能量分析器测量出整个DL产生的正离子束;在电抗性气体中,DLs是在极低的压力下0.1至1毫托rr与等离子体膨胀一起形成的。DL保持静态,对边界条件的变化具有强力作用,其位置与磁场线有关。电压随着压力的下降,即电温在0.17毫升20伏左右,在低等离子体中产生的正离子束。在电子内气中也观测到DL,没有磁力范围大于0.5至10毫托尔的电磁层。电离子体的实际情况对外部参数和侵扰动元素非常敏感,并且它们以高负离子部分传播。电静探测测量和激光诱发光光分解,显示所有等参数在电密度、电子温度、电子温度低温、负电压电压电压低部分是独立的。