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Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame

An image showing the “boosted frame,” in which the observer moves at near light speed. The laser pulse is represented in blue and red; the wakefields are colored pale blue and yellow. In this frame, the plasma (yellow box) has contracted and the wavefronts are fewer and farther apart, resulting in far fewer calculations and faster results.

 Why it Matters: Laser driven plasma waves can produce accelerating gradients orders of magnitude greater than standard accelerating structures.  High quality electron beams of energy up to 1 GeV have been produced in just a few centimeters and 10-GeV stages being planned as modules of a conceptual future high energy collider.

Key Challenges:  Detailed simulations are required to realize the promise of much shorter particle accelerators using this technique.  Such simulations challenge or exceed current capabilities, in particular for high energy stages at GeV energies and beyond.

Accomplishments: Using novel numerical techniques based on special relativity, a new “boosted frame” can model laser-plasma wakefield accelerators in an optimal frame of reference,  producing up to six orders of magnitude speed-up in calculations from first principles of stages in the 1 TeV range, which is three orders of magnitude higher than the higher speedup reported previously for a 1-10 GeV range stage. For a 10 GeV stage, the speedup is over four orders of magnitude, which is one order of magnitude larger than the maximum speedup previously reported. The new results offered a verification of the scaling of plasma accelerators to the 1 TeV range and provide highly efficient tools for the detailed designs of experiments on new lasers such as BELLA.

Principal Investigator: Cameron Geddes, LBNL

More Information:  See  J.-L. Vay, C. G. R. Geddes, E. Cormier-Michel, and D. P. Grote, “Effects of hyperbolic rotation in Minkowski space on the modeling of plasma accelerators in a Lorentz boosted frame,” Phys. Plasmas 18, 030701 (2011), DOI:10.1063/1.3559483

See also, https://www.nersc.gov/news-publications/news/science-news/2011/boosting-the-next-wave-of-accelerators

 

Snapshot from a 10 GeV LPA stage boosted frame simulation. The image shows an externally injected electron bunch (middle) riding a density wake excited by an intense laser pulse (right), propagating in a 0.65 m long plasma channel.