NIF Sets Power and Energy Records

Power conditioning operator Seth Robinson conducts tests in one of the four NIF capacitor bays. The capacitor bays house NIF’s power conditioning system. Credit: Damien Jemison.

In the early hours of March 10, 2009, NIF made laser physics history by firing all 192 laser beams into the heart of the Target Chamber, delivering 1.098 megajoules (MJ) of ultraviolet (UV) energy in a pulse lasting a few billionths of a second. The event marked the first time any laser facility surpassed the megajoule barrier, and it started NIF on a continuing journey to set more power and energy records.

Nine years later, the NIF laser system fired 2.15 MJ of UV energy to the Target Chamber, a 15 percent improvement over the facility’s 1.8-MJ design specification.

“NIF’s users are always asking to use more energy in their experiments, because higher energies enhance the science NIF can deliver in support of the Stockpile Stewardship Program.”

—NIF Director Mark Herrmann

Senior optics assembly technician Frank Arredondo inspects the glass mid-plane section of a plasma electrode Pockels cell, an optical switch that enables NIF’s multi-pass amplification capability. Credit: James Pryatel

Each milestone along the way gave scientists the ability to demonstrate the highest energy NIF can safely deliver with its optics and laser configurations, thus expanding the boundaries of the science NIF can explore. The journey required painstaking research to get the most out of amplifiers and thousands of precision optical components.

Optics are an essential element of the NIF laser system. Continuous research and development efforts have put NIF’s optics at the cutting edge of material science and technology and play a crucial role in raising the laser’s energy and power thresholds. These breakthroughs have reduced the level of damage initiation and growth in the optics and led to a reduced cost to mitigate existing damage spots.

Based on the successful 2.15-MJ demonstration, NIF is working with LLNL’s ignition program to execute the first ignition experiments that utilize this enhanced energy capability. Looking ahead, this is the first major step toward extending NIF’s energy and power output through technology development and laser research.

NIF’s Energy Milestones:

• February 2009: NIF fires all 192 laser beams for the first time, sending an average of 420 joules of UV laser energy through each beamline’s final optics.
• March 2009: NIF delivers 1.098 MJ of UV energy to the Target Chamber.
• October-November 2010: NIF sets world records for laser energy delivered to an inertial confinement fusion target (1.3 MJ) and neutron yield (300 trillion neutrons), a measure of the amount of fusion energy generated.
• December 2011: A 1.4-MJ layered cryogenic deuterium-tritium (DT) shot produces a yield of 7×10¹⁴ (700 trillion) neutrons.
• March 2012: A 192-laser shot delivers 1.875 MJ of UV laser energy in a pulse 23 billionths of a second long. Later that summer, NIF delivers 500 trillion watts of peak power, more than 1,000 times more power than the United States uses at any given moment.
• September 2013: A cryogenic layered DT implosion experiment generates about 5×10¹⁵ (five quadrillion) neutrons and about 14 kilojoules (kJ) of fusion energy, almost 75 percent more than NIF’s previous record yield set earlier in the year.
• November 2013: NIF beams deliver a record 1.91 MJ of UV light to the drive hohlraum in a 15.8-nanosecond shaped pulse.
• February 2014: A shot produces a total yield of 9.6×10¹⁵ neutrons, or 27 kJ of fusion energy.
• August 2017: An experimental campaign generates a total fusion neutron yield of 1.9×10¹⁶ (19 quadrillion) and 53 kJ of fusion energy, nearly double the previous record.
• January 2018: A shot produces a neutron yield of 2.0×10¹⁶ and 55 kJ of fusion energy.
• May 2018: NIF delivers 2.15 MJ of UV laser energy to the Target Chamber.

Workers install a laser glass slab in a line replaceable unit that was assembled in the NIF Optics Assembly Building cleanroom.

Next Up: Efficiency Improvements