Reduced indirect drive RT instability growth using a decaying first shock at the National Ignition Facility

Hydrodynamic instabilities and poor fuel compression are major factors for capsule performance degradation in ignition experiments on the NIF. We are developing modified drives to reduce instability growth compared to previous ignition pulses whilst maintaining the low fuel adiabat needed for increased compression. Laser drive profiles with a decaying first shock (``adiabat shaping'') were developed that alter the Richtmyer-Meshkov growth phase and reduce the subsequent inflight Rayleigh-Taylor growth. Using in-flight x-ray radiography of 1D ripples at various wavelengths, the first growth measurements using these new shaped drives will be presented for 3-shock and 4-shock designs.