Abstract:
Using numerical integrations of the Boussinesq equations in rotating cylindrical domains with realistic
boundary conditions, we have computed the value of the largest Lyapunov exponent lambda_1 for a variety of aspect
ratios and driving strengths. We study in particular the domain chaos state, which bifurcates supercritically from the conducting fluid state and involves extended propagating fronts as well as point defects. We compare
our results with those from Egolf et al., [Nature 404, 733 (2000)], who suggested that the value of lambda_1 for the
spiral defect chaos state of a convecting fluid was determined primarily by bursts of instability arising from
short-lived, spatially localized dislocation nucleation events. We also show that the quantity lambda_1 is not intensive
for aspect ratios Gamma over the range 20< Gamma <40 and that the scaling exponent of lambda_1 near onset is consistent with
the value predicted by the amplitude equation formalism.
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