World's most powerful X-ray laser recreates conditions at the center of a star

SLAC's LCLS is the world's most powerful X-ray laser (Photo: University of Oxford/Sam Vinko)

To say things are really heating up at the US Department of Energy's SLAC National Accelerator Laboratory isn't just a bad pun, it's one hell (sorry) of an understatement. An Oxford-led team used the Stanford-based facility that houses the world's most powerful X-ray laser to create and probe a 2-million-degree Celsius (or about 3.6 million degrees Fahrenheit) piece of matter. The experiment allowed the scientists the closest look yet at what conditions might be like in the heart of the Sun, other stars and
planets.
"Making extremely hot, dense matter is important scientifically if we are ultimately to understand the conditions that exist inside stars and at the center of giant planets within our own solar system and beyond," explained University of Oxford lead author Sam Vinko.
The research was recently published in the journal Nature and was conducted using SLAC's Linac Coherent Light Source (LCLS), which is capable of firing laser pulses a billion times brighter than any other X-ray source around today.
The scientists didn't just create a tiny faux star in a lab out of thin air, though - the LCLS' pulses were directed at a minuscule piece of aluminum foil to create a solid plasma referred to as "hot dense matter."
If you're sitting in your kitchen eyeing that box of aluminum foil sitting next to your microwave, don't get any big ideas about creating a mini-star in the comfort of your own home. Your appliances aren't quite on par with what they've got in-house at SLAC.
"The LCLS, with its ultra-short wavelengths of X-ray laser light, is the first that can penetrate a dense solid and create a uniform patch of plasma - in this case a cube one-thousandth of a centimeter on a side - and probe it at the same time," says Bob Nagler, an LCLS instrument scientist at SLAC.
Nagler explains that it's been possible for a while to create plasma from gases and study it with conventional lasers, but LCLS is the first tool that can do the same with a solid. In fact, the same issue of Nature also reports that the LCLS is the world's first atomic X-ray laser providing "a penetrating view into the world of atoms and molecules," according to physicist Nina Rohringer who worked on the project at SLAC.
The resulting measurements scientists gain from creating and examining super-hot matter will be plugged into different theories and computer simulations, and could even help recreate the nuclear fusion process that powers stars.
"Those 60 hours when we first aimed the LCLS at a solid were the most exciting 60 hours of my entire scientific career," said Justin Wark, leader of the Oxford group. "LCLS is really going to revolutionize the field, in my view."