Micromagnetics Theory of Bubble-Domain Collapse

By deriving the complete Lagrangian and Rayleigh-Gilbert dissipation functions for an enclosed domain we have obtained a set of equations for the radial and translational motion of the domain. In this Letter we specialize to the case $\frac{\mathrm{dH}}{\mathrm{dx}}=0\mathrm{}$ and discuss the equations which govern radial motion only. We show that the critical collapse radius is a dynamic quantity which varies considerably from the value given by magnetostatics.