A reaction-diffusion system has kinetics with Jacobian entries , , , (dimensionless…

PHYSICS · Multi-part · Fermi University Physics · Mathematical Methods for Physics · Thermal, Statistical & Complex Systems · Linear algebra and vector spaces

Many Parts, One Behaviour, Ch Pattern formation: instabilities that choose a wavelength

Problem

A reaction-diffusion system has kinetics with Jacobian entries fu=0.8f_u=0.8, fv=−1.2f_v=-1.2, gu=1.5g_u=1.5, gv=−1.0g_v=-1.0 (dimensionless model units) at a uniform stationary state, with diffusion coefficients Du=1D_u=1 for the activator uu and DvD_v for the inhibitor vv (same units). ((a)) Show that the uniform state is stable in the absence of diffusion. ((b)) Derive the general Turing condition from h(q2)=det⁡(J−q2D)h(q^2)=\det(\mathbf J - q^2\mathbf D) and find the minimum ratio Dv/DuD_v/D_u at which a Turing instability first appears. ((c)) Find the critical wavenumber qcq_{\rm c} and the pattern wavelength Λc\Lambda_{\rm c} at that ratio.

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