Magnetic fields generated by the Rayleigh-Taylor instability were measured in laser-accelerated planar foils using ultrafast proton radiography. Thin plastic foils were irradiated with ∼4-kJ, 2.5-ns laser pulses focused to an intensity of ∼10(14)  W/cm(2) on the OMEGA EP Laser System. Target modulations were seeded by laser nonuniformities and amplified during target acceleration by the Rayleigh-Taylor instability. The experimental data show the hydrodynamic evolution of the target and MG-level magnetic fields generated in the broken foil. The experimental data are in good agreement with predictions from 2-D magnetohydrodynamic simulations.

Cryogenic-deuterium-tritium ͑DT͒ target compression experiments with low-adiabat ͑␣͒, multiple-shock drive pulses have been performed on the Omega Laser Facility ͓T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 ͑1997͔͒ to demonstrate hydrodynamic-equivalent ignition performance. The multiple-shock drive pulse facilitates experimental shock tuning using an established cone-in-shell target platform ͓T. R. Boehly, R. Betti, T. R. Boehly et al., Phys. Plasmas 16, 056301 ͑2009͔͒. These shock-tuned drive pulses have been used to implode cryogenic-DT targets with peak implosion velocities of 3 ϫ 10 7 cm/ s at peak drive intensities of 8 ϫ 10 14 W / cm 2 . During a recent series of ␣ ϳ 2 implosions, one of the two necessary conditions for initiating a thermonuclear burn wave in a DT plasma was achieved: an areal density of approximately 300 mg/ cm 2 was inferred using the magnetic recoil spectrometer ͓J. A. Frenje, C. K. Li, F. H. Séguin et al., Phys. Plasmas 16, 042704 ͑2009͔͒. The other condition-a burn-averaged ion temperature ͗T i ͘ n of 8-10 keV-cannot be achieved on Omega because of the limited laser energy; the kinetic energy of the imploding shell is insufficient to heat the plasma to these temperatures. A ͗T i ͘ n of approximately 3.4 keV would be required to demonstrate ignition hydrodynamic equivalence ͓Betti et al., Phys. Plasmas 17, 058102 ͑2010͔͒. The ͗T i ͘ n reached during the recent series of ␣ ϳ 2 implosions was approximately 2 keV, limited primarily by laser-drive and target nonuniformities. Work is underway to improve drive and target symmetry for future experiments.

Magnetic fields generated by the nonlinear Rayleigh-Taylor growth of laser-seeded three-dimensional broadband perturbations were measured in laser-accelerated planar targets using ultrafast proton radiography. The experimental data show self-similar behavior in the growing cellular magnetic field structures. These observations are consistent with a bubble competition and merger model that predicts the time evolution of the number and size of the bubbles, linking the cellular magnetic field structures with the Rayleigh-Taylor bubble and spike growth.