The computational framework INF&RNO (INtegrated Fluid & paRticle simulatioN cOde) allows for fast and accurate modeling, in 2D cylindrical geometry, of several aspects of laser-plasma accelerator physics. INF&RNO exploits the envelope model for the laser driver, and adopts either a PIC or a fluid description for the plasma. We report on the latest upgrade of the code, namely the PIC/fluid quasi-static modality, the improved laser envelope solver, and the ionization module.
INF&RNO is a 2D cylindrical (r-z) code designed to efficiently simulate the interaction of a short and intense laser pulse with a plasma. The code adopts an envelope model for the laser pulse and makes use of the (time averaged) ponderomotive force approximation to describe the interaction of the pulse with the plasma. The plasma can be modeled using either a PIC or a fluid description. Both modalities are integrated in the same computational framework. Concerning the numerical aspects, all the spatial derivatives are represented using second order centered/upwind schemes. A 2nd or a 4th order Runge-Kutta scheme is used to advance the plasma quantities and the wakefield in time-explicit calculations, while a 2nd order implicit Crank-Nicolson scheme is used for the laser envelope solver. To maximize computational efficiency the plasma wakefields and laser envelope are represented on different computational grids.
We will report on the latest upgrade to the code, namely the quasi-static PIC/fluid modality, the improved laser-envelope solver, and the ionization module. The modular structure of the code allows for easy switching between the different modules. This allows investigation of a given problem by subsequently adding layers of physical complexity, facilitating the understanding of the detailed behavior and properties of the physical system of interest.
The code has been extensively validated against analytical solutions and compared with full 3D PIC simulations showing good agreement with 3D results together with a reduction by several orders of magnitude in the computational cost compared to a full 3D PIC code. With INF&RNO we can model laser-plasma accelerator (LPA) experiments where the laser-plasma interaction takes place over characteristic distances ranging from millimeters up to a meter in a reasonable time (a few hours/days) and on small computers.
INF&RNO is routinely used to support the experimental activity at the BELLA Center. We will will present some examples of application of the code to current and future BELLA experiments.
Supported by the U.S. Department of Energy under contract No. DE-AC02-05CH11231
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