Lasers for Fusion Energy
Recently, theoretical physicists from Imperial College London published a paper which details how an extremely rapid heating mechanism could be used to heat certain materials to ten million degrees in less than a million millionth of a second. Currently, their fellow scientists are scrambling to try and put the team’s method into practice.
For years, we've known that high-power lasers are an effective way of heating materials; scientists have been working with this process as part of the effort to create fusion energy. If you aren't aware, fusion energy comes from fusion reactions, which occur when two lighter atomic nuclei fuse together as a result of intense heat and pressure. When they combine, they form a heavier nucleus and some of the mass is converted into energy. That energy can then be used to power any number of devices.
In this new study, the physicists focused on a way to directly heat ions (particles which make up the bulk of matter). In previous methods that were used to heat material, the energy from the laser had to first heat the electrons in the target. These then heat the ions. Since it is a two step process, it obviously takes longer than just heating the ions.
Notably, in their research, the Imperial team found that, in certain materials, a high-intensity laser will create an electrostatic shockwave that can heat ions directly.
How it works
Usually, laser-induced electrostatic shockwaves will push ions ahead of them. This causes them to move away from the shockwave and not heat up. The team was able to overcome this by using advanced supercomputer modelling, which showed them that, if a material contains a specific combinations of ions, they will be accelerated by the shockwave at different speeds.
This causes friction, which in turn causes them to rapidly heat. They found that the effect would be strongest in solids with two ion types, such as plastics. Ultimately, this form of heating is predicted to be about 100 times faster than rates currently seen in fusion experiments using the world’s most energetic laser system at the Lawrence Livermore National Laboratory in California.