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Images of a wakefield produced by a 30 TW laser pulse in plasma of density 2.7 x 1018 cm-3. The color image is a 3D reconstruction of the oscillations, and the grey-scale is a 2D projection of the same data. These waves show curved wavefronts, an important feature for generating and accelerating electrons that has been predicted, but never before seen. Pic: mit.edu

The ability of these waves to accelerate electrons so strongly has opened up the possibility of creating an ultra-compact version of a high-energy particle accelerator, a device which currently exists only in large-scale facilities like the Stanford Linear Accelerator Center (SLAC) and the International Linear Collider (ILC) at Fermilab in the US, and CERN in Europe. High-energy particle accelerators (which work on the same basic principle as the wakefields, but have electric fields thousands of times weaker) have long been one of our primary resources for learning about the nature of matter, and have on a smaller scale become important as sources of specialized radiation for cancer therapy. But the conventional accelerator technology used to create them, and their enormous size (several miles in length) restricts their existence to only a handful of laboratories around the world, making their use for research or medicine very costly and exclusive. While conventional accelerators such as SLAC and ILC are likely to remain the solution for very high energies, a wakefield-based accelerator could potentially be a thousand times smaller, and would fit on a table-top in a typical hospital or university research lab, providing much greater access to researchers and patients alike.

A 30 TW pump pulse at 800 nm (red pulse) focuses into Helium gas driving the generation of the wakefield. A lens, spectrometer and CCD-device act together to form the holographic-strobe camera system. The accompanying two chirped pulses at 400 nm (rainbow pulses) act as the flash bulb to provide illumination. Pic: mit.edu

Source: MIT