Shadowgraphic and EUV Emission Studies of Low Energy Miniature Plasma Focus Device

Summary form only given. A miniature plasma focus has recently been successfully developed at our Plasma Radiation Sources Lab. The system operates at low energy range of about 100 -160 J (0.8 muF capacitor bank, ~ 50 nH, 16 -20 kV). In the present paper, we report the pinching evidence in this miniature plasma focus device using time resolved laser shadowgraphic techniques and time integrated optical imaging. For shadowgraphic purposes, a new but relatively simple detection system was developed using commercial Canon EOS 300D camera where the diagnostic laser and the miniature plasma focus were triggered by the camera itself. The use of this 6 Megapixel camera with its normal lens system not only provided the easy shadowgraphic system setup but also high resolution shadowgraphic images. The shadowgraphy and time integrated imaging were done for hydrogen as well as xenon seeded hydrogen gas miniature plasma focus operation. The enhancement in extreme ultra-violet radiation signal for xenon seeded hydrogen operation has been observed. The shadowgraphic images show that well defined current sheaths are formed at higher pressures of 10 mbar and above with good focusing evidence. The EUV emission however is low at these pressures. The operation of focus device at lower pressure though does not show focusing of current sheath but has much better EUV emission efficiency.