Li-Beam-Heated Hohlraum Experiments at Particle Beam Fusion Accelerator II

Thermal radiation experiments with 9-MeV Li beams have been performed at Particle Beam Fusion Accelerator II with a peak beam intensity of $1–2\mathrm{TW}/{\mathrm{cm}}^2$. The peak brightness temperature of the target was $58\pm 4\mathrm{eV}$. We obtained specific depositions of 800–1600 TW/g in the foam. Important features of desired hohlraum performance have been demonstrated. These include a near-Planckian spectrum, increased heating due to the presence of a high-Z wall, x-ray mean free paths greater than the target size between 200 and 280 eV, thermal x-ray emission more uniform than the incident ion energy, and a high-Z wall velocity less than 3 cm/μs.