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Theory of the Spatio-Temporal Dynamics of Transport Bifurcations
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
where is the local transition
power threshold and 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.Comment: 21 page Tex file, 10 postscript file
Crossed product of a C*-algebra by a semigroup of endomorphisms generated by partial isometries
The paper presents a construction of the crossed product of a C*-algebra by a
semigroup of endomorphisms generated by partial isometries.Comment: 22 page
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