DocumentCode :
790756
Title :
Imploding Z -Pinch Plasmas Formed From a Carbon Fiber
Author :
Klir, Daniel ; Kubes, Pavel ; Kravarik, Jozef
Author_Institution :
Fac. of Electr. Eng., Czech Tech. Univ., Prague
Volume :
34
Issue :
5
fYear :
2006
Firstpage :
2303
Lastpage :
2311
Abstract :
Z-pinch experiments, which are formed from a 15-mum diameter carbon fiber in a vacuum, were conducted using a simple capacitor bank. After the breakdown, a low-density coronal plasma was formed while the fiber diameter remained almost unchanged. This low-density corona (ion density of about 1016 cm-3) was carrying almost all the current of the order of 10 kA. When the current had built up, i.e., after about 150 ns, the implosion of the corona onto the central fiber occurred. The implosion velocity approached the value of 2middot105 m/s. When the imploded corona had reached the fiber, the dip in dI/dt, a voltage peak up to 10 kV and an extreme-ultraviolet (XUV) pulse of a 10-30-ns width were observed. XUV radiation was emitted from several bright spots, which corresponded to the interaction of m=0 instability necks with the dense core. The electron temperature and density were approximately 80 eV and 1019 cm-3, respectively. Although the presence of a fiber did not significantly suppress MHD instabilities, they were not disruptive. After the fiber ablation, i.e., after 500 ns, the material evaporated from the electrodes started to play a dominant role. When MHD instabilities had developed in the imploding plasma column, XUV, soft X-ray, and hard X-ray pulses were emitted from several bright spots, particularly near the anode. At that time, the voltage peak of up to 30 kV was detected. The measurement of voltage and current enabled the determination of a plasma resistance and the energetics of the Z-pinch
Keywords :
Z pinch; carbon fibres; corona; explosions; plasma X-ray sources; plasma density; plasma diagnostics; plasma instability; plasma magnetohydrodynamics; plasma production; plasma temperature; plasma transport processes; vacuum breakdown; 10 to 30 ns; 15 mum; 80 eV; C; MHD instabilities; Z-pinch experiments; bright spots; capacitor bank; carbon fiber; coronal implosion; electrodes; electron density; electron temperature; extreme-ultraviolet pulse emission; fiber ablation; hard X-ray pulse emission; imploding Z-pinch plasmas; imploding plasma column; implosion velocity; instability necks; low-density coronal plasma; plasma diagnostics; plasma resistance; soft X-ray pulse emission; vacuum breakdown; Capacitors; Corona; Electric breakdown; Magnetohydrodynamics; Plasma density; Plasma measurements; Plasma x-ray sources; Space vector pulse width modulation; Ultraviolet sources; Voltage; Bright spots; Extreme ultraviolet (XUV) radiation; carbon; fiber; implosion; plasma diagnostics;
fLanguage :
English
Journal_Title :
Plasma Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0093-3813
Type :
jour
DOI :
10.1109/TPS.2006.878614
Filename :
1710118
Link To Document :
بازگشت