Create a large number of positrons in a small laboratory

[wolram]

http://www.sciencedaily.com/releases/2008/11/081117193019.htm

This new ability to create a large number of positrons in a small laboratory opens the door to several fresh avenues of anti-matter research, including an understanding of the physics underlying various astrophysical phenomena such as black holes and gamma ray bursts.

 

[oldman]

http://www.sciencedaily.com/releases/2008/11/081117193019.htm

This new ability to create a large number of positrons in a small laboratory opens the door to several fresh avenues of anti-matter research...

And perhaps a few avenues of interest here, as you say. A good use for solid gold --- always of interest in this part of the Deep South!

You may be the right person to ask about a related topic involving intense laser light: Photon-photon interactions. I gather that such interactions mediated by, say, virtual positron-electron pairs, are invoked to explain reactions observed in particle accelerators.

Do you know of any observations of laser-produced photons interacting with similar photons outside accelerators, as when high energy laser beams cross in empty space? I'd like to know more about the kind of interactions between photons that might occur in the plasma present in the very early universe.