This site uses cookies. By continuing to use this site you agree to our use of cookies. To find out more, see our Privacy and Cookies policy.
Skip to the content

Share this

Free weekly newswire

Sign up to receive all our latest news direct to your inbox.

Physics on film

100 Second Science Your scientific questions answered simply by specialists in less than 100 seconds.

Watch now

Bright Recruits

At all stages of your career – whether you're an undergraduate, graduate, researcher or industry professional – brightrecruits.com can help find the job for you.

Find your perfect job

Physics connect

Are you looking for a supplier? Physics Connect lists thousands of scientific companies, businesses, non-profit organizations, institutions and experts worldwide.

Start your search today

Blog

A factor of two

conference image

Worrying signs at the National Ignition Facility.

By Michael Banks in Boston

“A factor of two is not a small thing, it is quite a challenge,” says Robert McCory from the University of Rochester in New York.

McCory was speaking about the latest in laser-based fusion research (known as inertial confinement fusion) at the 2013 AAAS conference.

The National Ignition Facility (NIF), which began full operation in 2009, is based at the Lawrence Livermore National Laboratory in the US and is currently the world’s leading laser-based fusion device.

It uses a 1.8 MJ laser to create X-rays that act to rapidly heat and compress a capsule containing deuterium and tritium, which cause the hydrogen isotopes to fuse. Yet so far the facility has failed to achieve “ignition” – the point at which the fusion reactions generate enough heat to become self-sustaining. Indeed, the best shot so far at NIF has fallen short of the pressure needed to compress the fuel enough to produce ignition by a factor of two or three.

This has led to some to suggest that NIF needs to change course. The current method – indirect drive – uses X-rays rather than the light itself to heat the fuel capsule. But some say that direct drive should now be employed – where the laser light is shone directly onto the fuel capsule.

However, McCory, who runs a direct-drive experiment at Rochester called OMEGA, has done simulations showing how results on his machine could scale to NIF conditions.

“If we take our best OMEGA shot and extrapolate it to NIF then we would still be a factor of two or three away in required pressure from ignition,” says McCory.  ”And there is still physics that does not scale well, so there are added uncertainties.”

Researchers working on both direct and indirect methods are now looking at ways to get around the factor of two problem, which include trying to remove impurities in the plastic shell that holds the fusion fuel.

NIF scientists still remain confident, however, that they will overcome these barriers. Hopefully, policy-makers will have the same amount of patience.

This entry was posted in AAAS Annual Meeting 2013 and tagged , . Bookmark the permalink.
View all posts by this author  | View this author's profile

Leave a comment

Your e-mail address will not be published. Required fields are marked *

Guidelines

  • Comments should be relevant to the article and not be used to promote your own work, products or services.
  • Please keep your comments brief (we recommend a maximum of 250 words).
  • We reserve the right to remove excessively long, inappropriate or offensive entries.

Show/hide formatting guidelines

Tag Description Example Output
<a> Hyperlink <a href="http://www.google.com">google</a> google
<abbr> Abbreviation <abbr title="World Health Organisation" >WHO</abbr> WHO
<acronym> Acronym <acronym title="as soon as possible">ASAP</acronym> ASAP
<b> Bold <b>Some text</b> Some text
<blockquote> Quoted from another source <blockquote cite="http://iop.org/">IOP</blockquote>
IOP
<cite> Cite <cite>Diagram 1</cite> Diagram 1
<del> Deleted text From this line<del datetime="2012-12-17"> this text was deleted</del> From this line this text was deleted
<em> Emphasized text In this line<em> this text was emphasised</em> In this line this text was emphasised
<i> Italic <i>Some text</i> Some text
<q> Quotation WWF goal is to build a future <q cite="http://www.worldwildlife.org/who/index.html">
where people live in harmony with nature and animals</q>
WWF goal is to build a future
where people live in harmony with nature and animals
<strike> Strike text <strike>Some text</strike> Some text
<strong> Stronger emphasis of text <strong>Some text</strong> Some text
WordPress Appliance - Powered by TurnKey Linux