A technique developed to accurately simulate the amplification of back-reflected light through a multi-petawatt laser system is presented.Using the Frantz–Nodvik equation,we developed an iterative algorithm to simula...A technique developed to accurately simulate the amplification of back-reflected light through a multi-petawatt laser system is presented.Using the Frantz–Nodvik equation,we developed an iterative algorithm to simulate the amplification of the main beam as it propagates through solid-state multipass amplifiers,while also accounting for back-reflections from experimental targets and the residual gain within the crystals.Our technique builds on the theoretical model by estimating the energy levels after multiple passes through all amplifiers and refining the simulated data using a brute-force optimization algorithm.We also demonstrate an application of this tool aimed at evaluating machine safety:optimizing the laser system to minimize crystal gain in the post-pulse regime and,consequently,the amplification of back-reflections,while taking advantage of the B-integral.展开更多
The influence of a self-focused beam on the stimulated Raman scattering(SRS)process in collisional plasma is explored.Here,collisional nonlinearity arises as a result of non-uniform heating,thereby causing carrier red...The influence of a self-focused beam on the stimulated Raman scattering(SRS)process in collisional plasma is explored.Here,collisional nonlinearity arises as a result of non-uniform heating,thereby causing carrier redistribution.The plasma density profile gets modified in a perpendicular direction to the main beam axis.This modified plasma density profile greatly affects the pump wave,electron plasma wave(EPW)and back-scattered wave.The well-known paraxial theory and Wentzel-Kramers-Brillouin approximation are used to derive second-order ordinary differential equations for the beam waists of the pump wave,EPW and the scattered wave.Further to this,the well-known fourth-order Runge-Kutta method is used to carry out numerical simulations of these equations.SRS back-reflectivity is found to increase due to the focusing of several waves involved in the process.展开更多
The method of studying crystals using divergent X-ray beams emitted by a point source is known as the divergent beam method. If the X-ray source is inside a crystal and the characteristic radiation is emitted by the c...The method of studying crystals using divergent X-ray beams emitted by a point source is known as the divergent beam method. If the X-ray source is inside a crystal and the characteristic radiation is emitted by the crystal itself, it is called the Kossel method. If the source is outside the crystal and the divergent展开更多
基金supported by contract PN 23210105 sponsored by the Romanian Ministry of Research,Innovation and Digitalizationthe IOSIN Funds for Research Infrastructures of National Interest+1 种基金the IMPULSE project funded by the EU’s Horizon 2020 research and innovation program under grant agreement No.871161project ELI-RO-19‘HighProtonPLas’,funded by IFA and through Project ELI-RO/DFG/2023-001 ARNPhot funded by the Institute of Atomic Physics Romania。
文摘A technique developed to accurately simulate the amplification of back-reflected light through a multi-petawatt laser system is presented.Using the Frantz–Nodvik equation,we developed an iterative algorithm to simulate the amplification of the main beam as it propagates through solid-state multipass amplifiers,while also accounting for back-reflections from experimental targets and the residual gain within the crystals.Our technique builds on the theoretical model by estimating the energy levels after multiple passes through all amplifiers and refining the simulated data using a brute-force optimization algorithm.We also demonstrate an application of this tool aimed at evaluating machine safety:optimizing the laser system to minimize crystal gain in the post-pulse regime and,consequently,the amplification of back-reflections,while taking advantage of the B-integral.
文摘The influence of a self-focused beam on the stimulated Raman scattering(SRS)process in collisional plasma is explored.Here,collisional nonlinearity arises as a result of non-uniform heating,thereby causing carrier redistribution.The plasma density profile gets modified in a perpendicular direction to the main beam axis.This modified plasma density profile greatly affects the pump wave,electron plasma wave(EPW)and back-scattered wave.The well-known paraxial theory and Wentzel-Kramers-Brillouin approximation are used to derive second-order ordinary differential equations for the beam waists of the pump wave,EPW and the scattered wave.Further to this,the well-known fourth-order Runge-Kutta method is used to carry out numerical simulations of these equations.SRS back-reflectivity is found to increase due to the focusing of several waves involved in the process.
文摘The method of studying crystals using divergent X-ray beams emitted by a point source is known as the divergent beam method. If the X-ray source is inside a crystal and the characteristic radiation is emitted by the crystal itself, it is called the Kossel method. If the source is outside the crystal and the divergent
