Analytic theory of ablation layer instability

An analytic theory of the stability of thin ablation fronts is developed. Large wavenumbers are found to be stabilized by lateral heat conduction; this results in maximum growth rate of order g/v at wavenumber of order g/v2, where g is the acceleration of the front and v the ‘‘exhaust’’ velocity of the ablated material. For typical ablation front parameters the model predicts that implosions with shell aspect ratios of at least 20 should be viable.