All the fusion experiments in the past were based on direct illumination of the target (pellet) with the laser beams from all sides.

The "modern" approach is to use indirect heating using:

The idea is to transfer the energy to the nuclear fuel uniformly from all sides.

The Hohlraum is a special cylindrical chamber, which is coated with gold from the inside.

The laser beams hit the inside of the Hohlraum cavity, which results in a high flux of x-rays .

These x-rays heat the pellet from all sides, as can be seen in figure 9.25.