Hohlraum

"What we would like to do is take the laser and shine the laser onto what we call a hohlraum, ❋ Unknown (2009)

A tiny chamber made of gold, called a hohlraum, is used to contain the pellet of heavy hydrogen fuel at the center of a fusion reaction at the National Ignition Facility. ❋ Unknown (2010)

This was done by encasing it in a gold cylinder called a hohlraum, pierced by holes through which the laser beams were shone. ❋ Unknown (2010)

The target will be held inside a tiny gold cylinder called a hohlraum, about the size of a pencil eraser. ❋ Unknown (2010)

Inside the hohlraum is a tiny pellet containing an extremely cold, solid mixture of hydrogen isotopes ❋ Unknown (2010)

The historic level of laser energy delivered is about 30 times the energy delivered by any other group of lasers in the world and was achieved by focusing the energy of 192 powerful laser beams into a pencil-eraser-sized cylinder containing a tiny spherical target called a hohlraum (pictured below). ❋ Unknown (2010)

In inertial confinement fusion (ICF) experiments, the energy of 192 powerful laser beams is fired into a small cylinder called a hohlraum, which contains a tiny spherical target filled with deuterium and tritium, two isotopes of hydrogen. ❋ Unknown (2010)

These good news were reported in a Glenzer et al.: Symmetric Inertial Confinement Fusion Implosions at Ultra-High Laser Energies Deuterium-tritium capsules (gold-plated hollow cylinders called "hohlraum" for "hollow area" in German) may be compressed and implode. ❋ Unknown (2010)

NIF uses an approach called indirect drive inertial fusion, in which the tiny capsule of heavy hydrogen fuel is centered inside a cavity called a hohlraum. ❋ Unknown (2010)

Laser beams enter through the two open ends of the hohlraum and are reflected in toward the fuel, heating it up to produce the fusion reaction. ❋ Unknown (2010)

Laser beams bombard the inside walls of the hohlraum, heating it and generating x-rays that cause the capsule to implode. ❋ Unknown (2010)

To do that, in these experiments at the Laboratory for Laser Energetics in Rochester, a second capsule was placed nearby and hit by another set of laser beams, producing a flash of protons to illuminate the first capsule, inside a hohlraum. ❋ Unknown (2010)

In order for the ignition to work, the capsule of deuterium and tritium - two heavy forms of the element hydrogen - must be nearly perfectly spherical, nearly perfectly placed at the center of the hohlraum cavity, and must implode in a nearly perfectly symmetrical way. ❋ Unknown (2010)