A laser plasma accelerator (LPA) has been used to power a free electron laser (FEL) for more than eight hours, delivering stable pulses of coherent light. The system was created in the US by researchers at the company Tau Systems and Lawrence Berkeley National Laboratory . The team says that its achievement represents a major breakthrough in stability for LPA-driven FELs, which could someday make coherent UV and X-ray pulses more accessible to academia and industry. An FEL creates bright pulses of coherent light – usually in the ultraviolet-to-X-ray portion of the electromagnetic spectrum. These pulses are used in a wide range of research including physics, chemistry, biology and materials science. The pulses are created by sending bunches of high-energy electrons through a device called an undulator, which applies a transverse magnetic field that alternates in direction as the bunch propagates. As the electrons are accelerated back and forth by the field they emit light.…