Pictures of the fastest moving waves ever photographed were presented this morning at APS Division of Plasma Physics meeting in Philadelphia. These shots are more than your typical pretty pictures – they represent a major advance in wakefield accelerator technology, a technology that could make tabletop high-energy particle accelerators a reality.
The matter waves, which are oscillations moving through a plasma, are known as wakefields because they are created in the wake of an ultra-intense laser pulse. The waves travel at 99.997% of the speed of light and generate electric fields exceeding 100 billion
The ability to create huge electric fields makes wakefields a promising method for shrinking the size of accelerators from miles long (like those at the Stanford Linear Accelerator Center, FermiLab and CERN) to tabletop. Small accelerators would allow universities and hospitals to take advantage of the research and medical applications afforded by an accelerator without competing for time at a major particle accelerator facility.
Much work remains before tabletop accelerators can be a reality – particularly in understanding the interactions between a wakefield, the accelerated electrons, and the laser pulse. The ability to photograph wakefields is exciting news for scientists because it allows them to explore these interactions and compare theoretical predictions to real data.
Researchers from the University of Texas designed a holographic-strobe camera to take these pictures. Their method, called Frequency Domain Holography, sends two additional laser pulses though the plasma along with the ultra-intense pulse. The additional pulses detect the oscillations and then travel through a spectrometer where they interfere and are analyzed.