Density-tailored Capillary Discharge

Advanced high energy electron accelerators based upon plasma laser acceleration rely on using capillary discharges for both forming the plasma and providing a means for guiding the intense laser beam over distances much longer than the Rayleigh range. Scaling these devices to TeV energy levels requires using long capillary discharges with relatively low on-axis electron densities while still maintaining a small matched laser spot size throughout the capillary and, at the same time, tapering the density along the capillary. Conventional capillary discharges cannot satisfy all these conditions simultaneously. We have developed a new type of capillary discharge that is capable of satisfying all these requirements simultaneously, as well as being able to scale to long lengths. It is able to provide electron density tailoring to suit not only the needs for plasma-based laser accelerators, but also for other plasma-based experiments and technologies. During Phase I, we will perform experiments to verify the model predictions for our new type of capillary discharge and design a prototype that will be built during Phase II. During Phase II, we will build and test the prototype. Our density-tailored capillary discharge would help plasma laser accelerators and other plasma- based technologies become marketable products, for example, creation of tabletop linear accelerators or x-ray generators. Compact accelerators can generate tunable, intense electromagnetic radiation for industrial, medical, defense, and homeland security applications, such as terahertz light for whole-body scanning and gamma rays for detection of special nuclear materials. Our device benefits these technologies by improving their efficiency and providing a means to scale to high electron energies, including reaching 1 TeV for collider applications.