Part 2 of 2 Parts (Please read Part 1 first)
For many scientists, the results of the NIF fusion tests confirm that the laboratory is now operating in a new regime. Researchers can now repeatedly duplicate a goal they have been pursuing for more than a decade. Tiny variation of the laser pulses or minor defects in the diamond capsule can still allow energy to escape which results in an imperfect implosion. However, the scientists now have a better understanding of the main variables at play and how to manipulate them.
Annie Kritcher is the NIF’s lead designer for this series of experiments. She said, “Even when we have these issues, we can still get more than a megajoule of fusion energy, which is good.”
It is a long way from the successes at the NIF to the goal of commercial nuclear fusion generated electricity being connected to the grid. However, although the NIF is currently home to the biggest laser in world, it is not well-suited to that task. The NIF’s laser system is very inefficient. More than ninety nine percent of the energy that goes into a single ignition attempt is lost before it can reach the target.
Developing more efficient laser systems is one of the main goals of the DoE’s new inertial-fusion energy research program. This month, the DoE announced forty two million dollars to be spent over four years to establish these three new research centers that will work towards this and other advances.
This investment is the first coordinated effort to develop not just the technologies, but also the workforces required for a future laser-fusion industry according to Carmen Menoni who is a physicist heading up the hub at Colorado State University.
So far, most government investments in fusion energy research have gone into devices called tokamaks. Tokamaks are donut shaped and utilize magnetic fields to confine fusion reactions. This approach is under development at ITER which is an international partnership to construct the world’s biggest fusion facility near Saint-Paul-lez-Durance, France. Tokamaks have also been the recipients of many fusion investments in the private sector. However, dozens of companies are pursuing other approaches.
The time for a dedicated laser-fusion program is right according to Menoni. The decision to pursue it would not have happened without the recent NIF success. Menoni said, “We now know it will work. What will take time is to develop the technology to a level where we can build a power plant.”
Back at the NIF, Kritchner’s latest series of experiments feature a seven percent boost in laser energy. This should lead to even bigger yields. The first experiment in this test series was one of the successful ignitions which took place on the 30th of October. It did not break the record but an input of two and two tenths megajoules of laser energy yielded an output of three and four tenths megajoules of fusion energy.
Kritcher attributes the fact that it did not break the record for energy yield growing pains with the new laser configuration. It is designed to create more energy in the same sized gold cylinder of the previous set of experiments. Before moving to a bigger cylinder, Kritcher
says that her team is going to focus on changes to the laser pulse in order to produce a more symmetrical implosion. She said, “We’ve got four experiments next year.”