Experiments illuminate supersonic radiation flow

September 10, 2015 by Breanna Bishop, Lawrence Livermore National Laboratory
A close-up of a Pleiades target installed on a NIF target positioner. The large sombrero-like shield is intended to block unconverted light from creating background radiation for the diagnostics measuring energy transfer.

A multi-institutional team of scientists fired the 26th and final shot of the Pleiades experimental campaign at the National Ignition Facility last month. The campaign has created a new scientific foundation for the study of supersonic radiation flow in astrophysical phenomena and in inertial confinement fusion physics.

Begun in 2011, the campaign was fielded by Los Alamos National Laboratory (LANL) in collaboration with the United Kingdom's Atomic Weapons Establishment (AWE) and supported by LLNL.

Pleiades was devised to study how energy propagates through material in the radiation-dominated and diffusive regime. This is a general scientific "problem" created in a range of plasmas, both astrophysical and in the laboratory. It also is a problem widely used to test and benchmark radiation hydrodynamics codes.

"The study of how radiation propagates through a plasma is of central importance to many areas of physics," said James Benstead, AWE campaign lead. "Important examples include the heating of ablators in indirect-drive experiments, heating through hohlraum walls and, in astrophysics, supernova explosions and the transport of radiation through star-forming regions. The Pleiades campaign allowed the simulation of radiation transport through plasmas to be tested experimentally in a constraining, supersonic and diffusive regime."

The team created a laboratory version of the general one-dimensional problem using a half-hohlraum X-ray source, which launched a supersonic and diffusive heat front into a cylinder of foam material. This allowed the researchers to study the basic radiation flow phenomena as well as constrain the properties of the materials used in a previously inaccessible regime.

"Comparison of the data with simulations shows that our simulation capability is very good," said Alastair Moore, LLNL campaign lead. "When we correct the material properties data within its inherent uncertainty, we get an excellent match to the radiation transport results."

The high-temperature hohlraum that was developed for the Pleiades campaign will be a good platform to study radiation flow through other low-density foam media to constrain material properties, Moore added. In addition, the Pleiades X-ray drive setup is being applied as part of the Menkar and Cepheus campaigns fielded at NIF by AWE and LANL, respectively. The Pleiades platform also was used for a recent performance qualification shot of a new diagnostic.

"The Pleiades campaign was an excellent example of not just a successful collaboration between AWE and LANL, but also of NIF being used as a user facility by these labs," Benstead said.

Explore further: Measuring the National Ignition Facility's inferno

Related Stories

Measuring the National Ignition Facility's inferno

June 11, 2015

The smooth blue sphere of the National Ignition Facility's (NIF) target chamber bristles with diagnostics—nuclear, optical and X-ray instruments that together provide some 300 channels for experimental data. These diagnostics ...

Unlocking the secrets of star creation

April 30, 2015

On April 1, 1995, the Hubble Space Telescope (link is external), now celebrating its 25th anniversary, captured the famous images of the "Pillars of Creation" in the Eagle Nebula. Twenty years later to the day, the NIF Team ...

Laser sets records for neutron yield, laser energy

November 8, 2010

(PhysOrg.com) -- The National Nuclear Security Administration's National Ignition Facility (NIF) has set world records for neutron yield and laser energy delivered from laser-driven capsules to an inertial confinement fusion ...

Omega Laser Facility completes record 25,000 experiments

November 5, 2013

The National Nuclear Security Administration (NNSA) today announced that the Omega Laser Facility, a national user facility for NNSA that is located at and operated by the University of Rochester's Laboratory for Laser Energetics ...

Recommended for you

New insights into magnetic quantum effects in solids

January 23, 2019

Using a new computational method, an international collaboration has succeeded for the first time in systematically investigating magnetic quantum effects in the well-known 3-D pyrochlore Heisenberg model. The surprising ...

Rapid and continuous 3-D printing with light

January 22, 2019

Three-dimensional (3-D) printing, also known as additive manufacturing (AM), can transform a material layer by layer to build an object of interest. 3-D printing is not a new concept, since stereolithography printers have ...

Scientists discover new quantum spin liquid

January 22, 2019

An international research team led by the University of Liverpool and McMaster University has made a significant breakthrough in the search for new states of matter.

Researchers capture an image of negative capacitance in action

January 21, 2019

For the first time ever, an international team of researchers imaged the microscopic state of negative capacitance. This novel result provides researchers with fundamental, atomistic insight into the physics of negative capacitance, ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.