dorsal/arxiv
View SchemaTheory of the Spatio-Temporal Dynamics of Transport Bifurcations
| Authors | V. B. Lebedev, P. H. Diamond |
|---|---|
| Categories | |
| ArXiv ID | plasm-ph/9609001 |
| URL | https://arxiv.org/abs/plasm-ph/9609001 |
| DOI | 10.1063/1.872196 |
Abstract
The development and time evolution of a transport barrier in a magnetically confined plasma with non-monotonic, nonlinear dependence of the anomalous flux on mean gradients is analyzed. Upon consideration of both the spatial inhomogeneity and the gradient nonlinearity of the transport coefficient, we find that the transition develops as a bifurcation front with radially propagating discontinuity in local gradient. The spatial location of the transport barrier as a function of input flux is calculated. The analysis indicates that for powers slightly above threshold, the barrier location $x_b(t) \sim ( D_n t (P-P_c)/P_c)^{1/2},$ where $P_c$ is the local transition power threshold and $D_n$ is the neoclassical diffusivity . This result suggests a simple explanation of the high disruptivity observed in reversed shear plasmas. The basic conclusions of this theory are insensitive to the details of the local transport model.
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"abstract": "The development and time evolution of a transport barrier in a magnetically\nconfined plasma with non-monotonic, nonlinear dependence of the anomalous flux\non mean gradients is analyzed. Upon consideration of both the spatial\ninhomogeneity and the gradient nonlinearity of the transport coefficient, we\nfind that the transition develops as a bifurcation front with radially\npropagating discontinuity in local gradient. The spatial location of the\ntransport barrier as a function of input flux is calculated. The analysis\nindicates that for powers slightly above threshold, the barrier location\n$x_b(t) \\sim ( D_n t (P-P_c)/P_c)^{1/2},$ where $P_c$ is the local transition\npower threshold and $D_n$ is the neoclassical diffusivity . This result\nsuggests a simple explanation of the high disruptivity observed in reversed\nshear plasmas. The basic conclusions of this theory are insensitive to the\ndetails of the local transport model.",
"arxiv_id": "plasm-ph/9609001",
"authors": [
"V. B. Lebedev",
"P. H. Diamond"
],
"categories": [
"plasm-ph",
"physics.plasm-ph"
],
"doi": "10.1063/1.872196",
"title": "Theory of the Spatio-Temporal Dynamics of Transport Bifurcations",
"url": "https://arxiv.org/abs/plasm-ph/9609001"
},
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