The NIF’s current director Ed Moses bridles at accusations that ignition was overemphasized. “I don’t think it was oversold or undersold. It just was.” Moses insists that “remarkable progress” has been made in the past 16 months, since the NIF began working with hydrogen-pellet targets. “The goal was to do the initial exploration of the ignition conditions and see where we were, which is what we’ve done.”
But there is likely to be less time for ignition experiments in the coming year, says Cook. Livermore will still control the program’s day-to-day operation, but the NNSA’s headquarters in Washington DC will set priorities as the facility expands its stockpile stewardship work. Already, the NIF has been able to address crucial questions about how energy passes from the fission stage of a nuclear weapon to its much more powerful fusion stage. Future research will assess the ‘boost phase’ of the weapon — during which a small quantity of deuterium and tritium at the center of the first stage is used to boost the initial fission phase of the explosion.
The shift in priorities worries Riccardo Betti, a laser fusion researcher at the University of Rochester in New York. “They have to make sure that the ignition effort doesn’t become subcritical,” he warns.
Keeping momentum in the ignition campaign may be crucial, because many in Congress still believe in the energy-research mission being pushed by the lab. Lawmakers have mandated that a new plan for reaching ignition be delivered to them by the end of the month. Politicians are ready to accept that it may take longer than originally stated, but they need to see evidence that it is on course, the congressional staff member says: “It can’t just be an open-ended: ‘Just give us money, we promise we will do good science’.” And if the NIF fails to reach its ignition goal in a few more years? “Then we’ll have to evaluate whether it’s worth continuing to fund the facility.”