Design and Simulation of Capillary Discharge Plasmas for Next Generation Plasma Wakefield Accelerators

Fundamental improvements to the energy, brightness, and stability of lepton beams from next generation plasma-based accelerators are essential to maintain rapid innovation and scientific productivity within the field of advanced accelerators. Meeting these goals will require improvements in the understanding, design, and control of the plasmas used for both injection and acceleration. Laser plasma accelerators benefit from shaped densities that match the beam distribution and permit diffraction-free propagation, while beam-driven wakefield accelerators for positrons require near-hollow channel profiles. Capillary discharge technology promise tailored profiles for both types of sources, as well for lenses necessary for coupled acceleration. However, improved modeling tools are required to advance the technology.We propose to simulate capillary discharge plasmas using the publicly available multiphysics code FLASH. We will develop the tools to optimize plasma density for matching and guiding of drive beams and intense lasers, as well as the inclusion of embedded gas jets for downramp injection. We will also demonstrate their viability in generating hollow-channel plasmas for positron wakefield acceleration and other advanced concepts. We will facilitate easy exchange of data between FLASH and community PIC codes for simulating laser-plasma accelerators, with the goal of permitting self-consistent start-to-end simulations of plasma accelerators. We will simulate a capillary discharge waveguide with FLASH in 2D and R-Z geometries and benchmark against previous work. We will individually parametrize radial and longitudinal profiles as a function of capillary conditions. We will demonstrate the capability to optimize these targets, as necessary for generating profiles such as a hollow channel. We will implement a prototype GUI for simulations of capillary discharge plasmas, based on our open source Sirepo architecture. Commercial Applications and Other Benefits: We will commercialize our open-source scientific application framework Sirepo to provide sophisticated simulation support and consulting services for targeted industry and research partners. The Sirepo platform is designed to support a diverse array of software for modelling hydrodynamics, plasma physics, beam physics, and nanoscale device multi physics. Our target customers are businesses interested in computation fluid dynamics simulations, which have industrial applications in automotive, aerospace, defense, and energy markets. In addition to direct sales and presentations at conferences and trade shows, Radia Soft will build and brand an active online community and a viable ecosystem to support this business model.