Nature Photon. http://doi.org/nsx (2013)

Credit: © 2013 NPG

It is not hard to imagine the consequences of setting a field on fire. But what happens when an intense femtosecond laser burns though a micrometre-sized field — an array of nanowires? Michael Purvis and colleagues have done the experiment and found that it's a good way of producing dense, ultra-hot plasmas, rivalling those created in the pursuit of thermonuclear fusion.

Purvis et al. used few-micrometre-long nickel and gold nanowires (pictured) closely packed together at distances smaller than the wavelength of the laser. The femtosecond pulse penetrates deeply into the array, where it is completely absorbed. Numerical simulations show that as the energy is sucked in, the nanowires heat up and explode, generating a plasma of highly ionized atoms. The plasma expands rapidly, filling up all available space — but because the laser pulse is very short, its energy is efficiently absorbed before the critical density is reached. Using this technique, it might be possible to produce laboratory-made plasmas that approach the density and temperature conditions found in the centre of the Sun.