Abstract
Recent experiments have observed extremely sharp and complex structures in the ac susceptibility of the Condon domain phase in a high-density two-dimensional electron gas. Understanding of these structures requires a theoretical analysis of the dynamics of domain-wall motion. The present paper offers a theoretical framework for this analysis. Two phenomena are dealt with in detail: domain-wall resonance and a bending-mode resonance similar to the helicon-wave-like state seen in superconductors.