A new technical breakthrough has led to the creation of a “spark plug” for nuclear fusion

Maximizing the energy output of nuclear fusion is a crucial milestone in establishing it as the primary energy source for the future. Thus far, the accomplishment has been limited to a single system – the inertial fusion method used by the National Ignition Facility (NIF). Recent research on a comparable methodology indicates that the NIF may face competition in the field of inertial fusion.

Nuclear fusion, the process by which stars get their energy, is the predominant source of energy in the universe. However, replicating this phenomenon on Earth is challenging due to our inability to compress hydrogen to the same extent that gravity does in the stellar core. In order to circumvent that stipulation, the inertial fusion method employs lasers to compress a small, dense mass of fuel to such an extent that it undergoes ignition.

The NIF employs an indirect approach. Their technology utilizes very potent lasers, which are directed into a container known as a hohlraum, where they are transformed into x-rays. The x-rays subsequently compress the fuel pellet and generate energy. The fusion strategy described in recent study by experts at the University of Rochester involves the direct impact of lasers on the fuel pellet.

They have shown their invention known as the spark plug. The laser system has about one hundred times less power compared to the NIF system, however it successfully achieved fuel capsule compression and initiated nuclear fusions. Although the energy was little, it indicated the presence of fusing plasma, proving that the high temperature was not only due to the plasma.

“Exceeding the internal energy content of the fusion location by generating more fusion energy is a significant milestone,” said Dr. Connor Williams, the primary author of the first publication and now a staff scientist at Sandia National Labs, specializing in radiation and ICF target design. “That is an essential prerequisite for any future accomplishments, such as the combustion of plasmas or the attainment of ignition.”

The study used the OMEGA laser, which has the distinction of being the most expansive laser in the academic sphere. However, the NIF’s power is far greater. The crew was captivated by the prospect of modeling the potential outcomes of using such a laser, and the simulations have shown great promise.

“Direct drive exhibits numerous advantageous characteristics for fusion energy in comparison to indirect drive, particularly if one can ultimately develop the spark plug and compress fuel,” said Dr. Varchas Gopalaswamy, the primary author of the second research. “Once the OMEGA results are adjusted to match laser energies in the range of a few megajoules, it is anticipated that the fusion reactions will reach a state of self-sufficiency, known as ‘burning plasmas’.”

Despite the accumulation of discoveries and record-breaking achievements using this and other techniques, the path towards achieving commercially viable nuclear fusion is very lengthy. This experiment offers viable alternatives to established methodologies.

The articles are published by Nature Physics at these two locations: here and here.