Million degree laser could usher in age of fusion energy

Million degree laser could usher in age of fusion energy


Two-million degrees Fahrenheit.

That is temperature produced by a new laser beam, according to the U.S. Department of Energy’s SLAC National Accelerator Laboratory.

The department, which on Wednesday announced the successful experiment of the fastest and purest x-ray laser pulses ever achieved, said the laser could achieve temperatures as hot as 3.6 million degrees Fahrenheit — hotter than the sun’s corona. Scientists say the laser beam is billion times brighter that any other man-made X-ray source, making it the brightest entity ever created.

The laser, known as the Linac Coherent Light Source or LCLS, is the first of its kind able to actually penetrate inside solid matter, according to research scientists. Using ultra-short wavelengths of its X-ray light, the laser ramps up the temperature by focusing its rapid-fire pulses from the beam on a piece of aluminum foil thinner than spider’s silk. Scientists said the result of the experiment was the creation of a material known as hot dense matter.

“The LCLS X-ray laser is a truly remarkable machine,” said Sam Vinko, a postdoctoral researcher at Oxford University and the paper’s lead author. “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.”

Scientists have long been able to create plasma from gases and study it with conventional lasers, said co-author Bob Nagler of SLAC, an LCLS instrument scientist. However, until now no tools were available for doing the same at solid densities that cannot be penetrated by conventional laser beams. The latest experiment could usher in a series of experiments examining how hot dense matter could be used to study a number of issues, including the formation of the universe.

Scientists say the results could also allow for real-time probing of chemical reactions and biological molecules at work — subcellular activity that is not currently observable. Researchers also noted that the laser could allow for testing existing theories and computer simulations of how hot, dense matter behaves under certain conditions.

Scientists also suggested that the technology behind the laser could some produce nuclear fusion, long heralded as a potentially unlimited and clean source of energy. Nuclear fusion occurs when two or more atomic nuclei join together to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy, and the process of is the driving force that powers active stars.

Scientists had first predicted that X-ray lasers could be put to such use way back in 1967, but it is only now, forty-five years later, that experimental science has caught up with the theory and made lasers like the LCLS possible.

In a separate study, the LCLS was harnessed to build the first-ever atomic-scale X-ray laser, a feat that could open up a whole new field of atomic imaging. The Department of Energy team said the pair of studies would likely require a number of various follow ups, as scientists continue to examine the results of the first batch of experiments.

Wednesday’s announcement comes as the Department of Energy has hit a number of laser milestones in recent months. The world’s largest laser, located at the National Ignition Facility (or NIF) in California, set new records on October 31 and November 2 of 2010. The NIF laser fired a shot of 300 trillion neutrons, the most neutrons ever yielded by a laser to date, and one step closer to the amount of neutrons needed to reach fusion ignition. On November 2, the team was able use the laser to create a temperature of six million degrees Fahrenheit — the highest X-ray drive energy ever achieved in an indirect drive ignition target.

Both papers were published today in Nature.