How to Make a Star

Image of a Dwarf Galaxy

Star-Formation Laboratory

The dwarf galaxy NGC 4214 is ablaze with young stars and gas clouds. Located around 10 million light-years away in the constellation of Canes Venatici (The Hunting Dogs), the galaxy’s close proximity, combined with the wide variety of evolutionary stages among the stars, make it an ideal laboratory to research the triggers of star formation and evolution. The National Ignition Facility is a star-formation laboratory right here on Earth. Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration

Recipe for a Small Star

All you need to make a star on Earth is a tiny amount of the right material, a really powerful laser, and a fraction of a second:

  • Take a hollow, spherical plastic capsule about two millimeters in diameter (about the size of a small pea)
  • Fill it with 150 micrograms (less than one-millionth of a pound) of a mixture of deuterium and tritium, the two heavy isotopes of hydrogen.
  • Take a laser that for about 20 billionths of a second can generate 500 trillion watts—the equivalent of five million million 100-watt light bulbs.
  • Use all that laser power to create x rays that blow off the surface of the capsule.
  • Wait 10 billionths of a second.
  • Result: one miniature star.
Steps to Ignition

In this process the capsule and its deuterium–tritium fuel will be compressed to a density many times that of solid lead, and heated to more than 100 million degrees Celsius (180 million degrees Fahrenheit)—hotter than the center of the sun. These conditions are just those required to initiate thermonuclear fusion, the energy source of stars.

By following our recipe, we would make a miniature star that lasts for a tiny fraction of a second. During its brief lifetime, it will produce energy the way the stars and the sun do, by nuclear fusion. Our little star will produce 10 to 100 times more energy than we used to ignite it.

Why NIF?

That might seem like a simple formula, but replicating the extreme conditions that foster the fusion process has been one of the most demanding scientific challenges of the last half-century.

The idea for the National Ignition Facility (NIF) grew out of a decades-long effort to capture the energy of the sun and the stars in the laboratory. Current nuclear power plants, which use fission, or the splitting of atoms to produce energy, have been pumping out electric power for nearly 70 years. But achieving nuclear fusion—combining hydrogen atoms to release enough energy for electricity production—has not yet been demonstrated to be viable.

Drawings of a NIF Hohlraum
All of the energy of NIF’s 192 powerful laser beams is directed inside a gold cylinder called a hohlraum, which is about the size of a dime. A tiny capsule inside the hohlraum contains atoms of deuterium (hydrogen with one neutron) and tritium (hydrogen with two neutrons) that fuel the ignition process.

Physicists have pursued a variety of approaches to achieve nuclear fusion in the laboratory and to harness this potential source of unlimited energy for future power plants. NIF uses a process called inertial confinement fusion (ICF) to create the necessary pressures and temperatures needed for ignition. See Achieving Fusion Ignition for a more detailed description of ICF.

For fusion burn and energy gain to occur, a special fuel consisting of the hydrogen isotopes deuterium and tritium must first implode into a tiny “hot spot” and then “ignite.” A primary goal for NIF is to achieve fusion ignition, in which the energy generated from the fusion reaction exceeds the energy absorbed by the target capsule—more energy “out” than “in.”

NIF was designed to produce extraordinarily high temperatures and pressures—tens of millions of degrees and pressures many billion times greater than Earth’s atmosphere. These conditions currently exist only in the cores of stars and planets and in nuclear weapons. In a star, strong gravitational pressure sustains the fusion of hydrogen atoms. The light and warmth that we enjoy from the sun, a star 93 million miles away, are reminders of how well the fusion process works and the immense energy it creates.