Explosively driven magnetic flux compression (MFC) has been object of research for more than three decades. Actual interest in the basic physical picture of flux compression has been heightened by a newly started Department of Defense (DoD) Multi-University Research Initiative. The emphasis is on helical flux compression generators comprising a hollow cylindrical metal liner filled with high explosives and at least one helical coil surrounding the liner. After the application of a seed current, magnetic flux is trapped and high current is generated by moving, i.e., expanding, the liner explosively along the winding of the helical coil. Several key factors involved in the temporal development can be addresses by optical diagnostics. 1) The uniformity of liner expansion is captured by framing camera photography and supplemented by laser illuminated high spatial and temporal resolution imaging. Also, X-ray flash photography is insensitive to possible image blur by shockwaves coming from the exploding liner. 2) The thermodynamic state of the shocked gas is assessed by spatially and temporally resolved emission spectroscopy. 3) The moving liner-coil contact point is a possible source of high electric losses and is preferentially monitored also by emission spectroscopy. Since optical access to the region between liner and coil is not always guaranteed, optical fibers can he used to extract light from the generator. The information so gained will give, together with detailed electrical diagnostics, more insight in the physical loss mechanisms involved in MFC.
A. A. Neuber et al., "Optical Diagnostics on Helical Flux Compression Generators," IEEE Transactions on Plasma Science, vol. 28, no. 5, pp. 1445-1450, Institute of Electrical and Electronics Engineers (IEEE), Oct 2000.
The definitive version is available at http://dx.doi.org/10.1109/27.901212
Mining and Nuclear Engineering
Keywords and Phrases
Electroexplosive Devices; Explosive Generators; Explosively Driven Magnetic Flux Compression; Helical Coil; Helical Flux Compression Generators; High Current Generation; High Explosives; Hollow Cylindrical Metal Liner; Liner Expansion; Magnetic Flux; Magnetic Flux Trapping; Optical Diagnostics; Optical Imaging; Photographic Applications; Pulse Generators; Pulsed Power Supplies; Seed Current; Shock Wave
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Article - Journal
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