Study of rapid ionisation for simulation of soft X-ray lasers with the 2D hydro-radiative code ARWEN

Abstract

Keywords:Transient ionisation Soft X-ray laser NLTE emissivity We present our fast ionisation routine used to study transient soft X-ray lasers with ARWEN, a twodimensional hydrodynamic code incorporating adaptative mesh refinement (AMR) and radiative transport.We compute global rates between ion stages assuming an effective temperature between singlyexcited levels of each ion. A two-step method is used to obtain in a straightforward manner the variation of ion populations over long hydrodynamic time steps. We compare our model with existing theoretical results both stationary and transient, finding that the discrepancies are moderate except for large densities. We simulate an existing Molybdenum Ni-like transient soft X-ray laser with ARWEN. Use of the fast ionisation routine leads to a larger increase in temperature and a larger gain zone than when LTE datatables are used.

Equation of state and opacities for warm dense matter

“…Also a time-dependent ionization routine has been developed [15] to get the charge state evolution including NLTE effects and then corrections to the opacities and EOS must be applied to account for this NLTE effects.…”

Modelización de las propiedades radiativas e interacción de láseres ultraintensos con la materia

“…Sin embargo, bajo ciertas condiciones la distribución de electrones no es Maxwelliana. Algunos grupos han tratado con éxito este problema en el pasado [112,45,102,2] con diferentes enfoques, aquí estamos interesados en la modelización de la interacción láser-materia en el rango de los rayos X, en particular aquí trataremos la interacción de láseres de electrones libres (XFEL) [153,147] y los láseres de rayos X basados en plasma [39,106]. En este régimen los materiales son iluminados por una fuente de rayos X monocromática, con energías de los fotones hasta varios keV que son capaces de fotoionizar capas electrónicas internas.…”

Towards soft X-ray imaging: results in plasma-based lasers and plenoptic imaging

“…There are some additional quantities computed with other different codes that are fed to the DAGON code in order to properly simulate the propagation of the seed beam along the plasma channel. Creation and subsequent hydrodynamical evolution of the plasma was modeled with ARWEN [33], a two-dimensional code created for plasma simulations with a hydrodynamical approach. Results obtained with ARWEN are the initial conditions for Particle-in-cell (PIC) codes, such as WAKE-EP [85], [103] or FBPIC (Fourier-Bessel Particle-In-Cell code) [68], modelling the intense IR pump laser propagation.…”

“…It is based on the Maxwell-Bloch equations with the slowly-varying envelope approximation (SVEA). The plasma creation and its hydrodynamical evolution towards the waveguide shape was previously simulated with ARWEN [97], [33] while the propagation of an IR beam through a plasma was modelled with PIC codes, such as WAKE-EP and FBPIC [68]. Albeit including many parallelizable options, DAGON code was running sequentially, thus taking substantially long times to perform simulations and not taking full advantage of the available hardware.…”