The Radical Promise of Nuclear Fusion

On December 5, 2022, we learned that fusion was possible on earth. 

The Lawrence Livermore Laboratory’s National Ignition Facility (NIF) lies about 50 miles east of San Francisco. A multibillion-dollar undertaking of the Department of Energy, home of all things nuclear in the United States, the NIF is the largest and most powerful laser on earth. Actually, it’s not just one laser—it’s 192 lasers lined up next to one another, spanning the length of two football fields. The light from these lasers is accelerated and amplified six times before being converted into ultraviolet light and targeted precisely onto a metal cavity that contains a tiny capsule filled with hydrogen isotopes. The lasers are shot at the capsule for a billionth of a second and produce a temperature 10 times hotter than that of the sun’s center.

At about 100 million degrees Celsius, hydrogen isotopes are colliding into each other with such immense speed that they begin to fuse. As they do, they release a blast of energy so powerful it pushes other hydrogen isotopes to fuse until all the fuel in the capsule is used up. 

This process of heating up the capsule to the point that all its fuel is consumed in a fusion reaction is called ignition. The concept is nearly equivalent to the act of producing enough friction to light a match. It sounds simple enough, but it has taken decades, billions of dollars, and hundreds of attempts to get right. For years, the NIF’s failed attempts led to it being ridiculed as the “Never Ignition Facility” or the “Nearly Ignition Facility,” so you can imagine the relief that ensued when the 13-year-old, $3.5 billion laser system finally managed to light fusion’s match. Upon hearing the news, Tammy Ma, who heads the fusion initiative and has worked at the Lawrence Livermore lab for over 14 years, burst into tears while waiting to board a plane.

Ultimately, the NIF laser beamed 2.05 mega joules of ultraviolet light at the fuel capsule, inducing a fusion reaction that released 3.15 megajoules of energy.