The Rayleigh-Taylor instability in direct-drive laser fusion

Achieving high energy gain in laser fusion will require the use of moderately-thin pellet shells. But thinner shells are expected to be more susceptible to break-up from the Rayleigh-Taylor instability. Calculations and experimental data thus far indicate that the growth rate of the Rayleigh-Taylor instability is reduced well below the classical value when the surface of the pellet shell is directly ablated by laser light. In addition, the mix of the cold DT shell with the hot ignitor may only slightly degrade the pellet yield. It may therefore be possible to successfully implode these moderately thin shells and produce gains of a few hundred, using a few-megajoule KrF laser driver.