Fusion, which repeats the same reaction as the sun, has long been viewed as an ideal energy source because of its potential to be safe, clean, inexpensive and reliable. Since the early 1960s, scientists have explored the possibility of using powerful lasers to compress the fusion material for long enough and at temperatures high enough to initiate ignition – the point at which the resulting inertial fusion energy output exceeds the energy input to the target.

In December 2022, scientists managed to ignite at the National Ignition Facility at Lawrence Livermore National Laboratory, but there are many obstacles to making fusion energy technically and commercially viable for mass production and consumption.

Researchers at the University of Rochester’s Laser Energy Laboratory (LLE) have experimentally demonstrated for the first time a method called dynamic shell formation that could help achieve the goal of creating a fusion power plant.

Researchers, including LLE Senior Scientist Igor Igumenshchev and Distinguished Scientist and Director of the LLE Theory Division and Associate Professor (Research) in the Department of Mechanical Engineering, Valery Goncharov, discuss their findings in a paper published in Physical Review. . Literature .

“This experiment demonstrated the feasibility of an innovative target concept suitable for affordable mass production of inertial fusion energy,” says Igumenshchev.

The traditional approach to the inertial energy of synthesis

In the traditional approach to inert fusion, a target consisting of a small amount of hydrogen fuel (in the form of hydrogen isotopes deuterium and tritium) is frozen in a solid spherical shell. The shell is then bombarded with lasers, heating the core fuel to extremely high pressures and temperatures. When these conditions are reached, the crust collapses and begins to ignite and melt.

The process releases a large amount of energy that could potentially power a carbon-neutral power station. But a fusion power plant, which is still hypothetical, would require around one million targets per day. Current methods of target setting using the frozen preparation process are expensive and targets are difficult to produce.

Dynamic shell formation is an alternative method of target generation in which a liquid droplet of deuterium and tritium is injected into a foam capsule. The capsule turns into a spherical shell when bombarded with laser pulses, which then explodes and collapses causing ignition. Because dynamic shell formation uses liquid targets, it does not require the expensive cryogenic layering used by traditional fusion inertial power generation methods. These goals will also be easier to achieve.

Goncharov first described dynamic shell formation in a paper in 2020, but the concept has not been proven experimentally. In a scaled-down proof-of-principle experiment, Igumenshchev, Goncharov and colleagues demonstrated a critical step by using the OMEGA LLE laser to create a sphere of polyethylene foam with a shell of the same density as a deuterium-tritium liquid fuel. in the dynamic shell concept.

Future research will require lasers with longer and more energetic pulses to create fusion using the dynamic bombardment technique, but current experimentation shows that dynamic bombardment may be possible as a route to more practical energy fusion reactors.

“Combining this targeted concept with the high-efficiency laser system currently under development at LLE will provide a very attractive avenue to fusion energy,” says Igumenshchev. Source