气压对大面积等离子体片电子密度分布的影响

利用脉冲磁约束线形空心阴极放电装置,在15mT磁场约束下,产生了持续时间为200μs、峰值放电电流为3A、面积为60cm×60cm的大面积等离子体片。采用快帧法和旋转空心阴极法,在90~210Pa内,利用朗缪尔探针首次获得了不同气压的等离子体片的厚度向电子密度分布及其演化构成的二维分布图;研究了在同等峰值放电电流条件下,等离子体片达到最大厚度向峰值电子密度时,气压对所需放电时间、最大厚度向峰值电子密度及电子密度半高宽的影响。结果表明:在相同的峰值放电电流条件下,等离子体片达到最大厚度向峰值电子密度的时间随气压的降低而减小;气压越低,最大厚度向峰值电子密度越大,电子密度半高宽越小。

Effects of pressure on the pulsed magnetic confinement linear hollow cathode discharge

Large planar plasma sheets with size of 60 cm60 cm, maximum current of 3 A and duration of 200 s, were obtained in a pulsed linear hollow cathode discharge device under 15 mT magnetic field confinement. The electron density 2-D distribution in the thickness direction and its evolution of plasma sheets with pressures between 90 Pa to 210 Pa were obtained by Langmuir probe using the fast frame function of oscilloscope and the rotating hollow cathode method. The effects of pressure on the time needed to reach the maximum peak density in the thickness direction, the maximum peak density and the full width at half maximum (FWHM) peak density, were investigated. The results show that, as the pressure decreased, the time reaching the maximum peak density in the thickness direction and the FWHM peak density diminished, while the maximum peak density in the thickness direction increased. These results could be utilized to manipulate the parameters of large planar plasma sheets.