The dynamics of bifurcating bright-spots in fiber Z-pinch plasmas
- Blackett Laboratory, Imperial College, London, SW72BZ (United Kingdom)
- Insitut fuer Experimentalphysik, Universitaet Duesseldorf (Germany)
Results are presented from the diagnosis of the optical and x-ray emission from {open_quotes}bright-spots{close_quotes} in carbon fiber Z-pinch experiments using the MAGPIE (Mega-Ampere Generator for Plasma Implosion Experiments) generator [I. H. Mitchell {ital et al.}, Rev. Sci. Instrum. {bold 67}, 1533 (1996)]. Inhomogeneities evolve very rapidly within the plasma with bright-spots becoming detectable after 15{endash}20 ns. After a short ({approximately}4ns) duration formation phase, these bright-spots exhibit highly dynamic behavior. Bifurcation of the bright-spots is observed giving rise to rapid axial motion at 1{endash}3{times}10{sup 5}ms{sup {minus}1}. The post-bifurcation bright-spots persist for up to 40 ns. Analysis of cross-filtered, time integrated, x-ray pinhole images yield bright-spot parameters during the formation phase (diameter {approximately}80{mu}m, temperature 250{endash}300 eV, ion number densities {approximately}2{times}10{sup 26}m{sup {minus}3}). With a spatial resolution of 175 {mu}m, the strong temperature and density gradients within the post-bifurcation spots can be resolved in gated x-ray images with 2 ns exposure times. After the dynamic phase of bright-spot evolution, the pinch enters a quiescent phase where the time scale for evolution is much longer. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 526927
- Journal Information:
- Physics of Plasmas, Vol. 4, Issue 8; Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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