Synchrotron radiation from a plasma wakefield accelerator
DOI: 10.1063/1.4796795
A mainstay of the materials-science and bioscience research communities, the synchrotron light source provides a powerful, though large and expensive, probe of substances from the exotic to the mundane. To shrink those synchrotrons from today’s giant user facilities to something that can fit in a basement room is the goal of a multinational team led by Dino Jaroszynski (University of Strathclyde, Glasgow, UK). In a first step, the physicists coupled a high-intensity femtosecond laser, a plasma, and an undulator—a series of magnets through which electrons wiggle—to generate bursts of narrowband visible light. The intense field of a laser pulse produces waves in the plasma and rapidly accelerates electrons in a very short distance. Those high-energy electrons then navigate the undulator, radiating as they go. In the figure, the black dots show the light from the electron pulse depicted in the inset, while the red dots are from a different shot. In these early experiments, only about 1 in 10 laser pulses produced monoenergetic electron bunches, but the researchers think improvements can greatly increase the reproducibility and stability of the shots. Because laser-wakefield synchrotrons would be compact, inexpensive, and able to radiate from x rays down to microwaves, Jaroszynski says they could enable a wide range of applications in research, medicine, and industry. (
