This is the first of a series of papers presenting the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks (MIST) project, a new comprehensive set of stellar evolutionary tracks and isochrones computed using MESA, a state-of-the-art open-source 1D stellar evolution package. In this work, we present models with solar-scaled abundance ratios covering a wide range of ages ($5 \leq \rm \log(Age)\;[yr] \leq 10.3$), masses ($0.1 \leq M/M_{\odot} \leq 300$), and metallicities ($-2.0 \leq \rm [Z/H] \leq 0.5$). The models are self-consistently and continuously evolved from the pre-main sequence to the end of hydrogen burning, the white dwarf cooling sequence, or the end of carbon burning, depending on the initial mass. We also provide a grid of models evolved from the pre-main sequence to the end of core helium burning for $-4.0 \leq \rm [Z/H] < -2.0$. We showcase extensive comparisons with observational constraints as well as with some of the most widely used existing models in the literature. The evolutionary tracks and isochrones can be downloaded from the project website at this http URL

https://iopscience.iop.org/article/10.3847/0004-637X/823/2/102/pdf

Mesa isochrones and stellar tracks (mist). i. solar-scaled models

Ion acceleration driven by superintense laser pulses is attracting an impressive and steadily increasing effort. Motivations can be found in the applicative potential and in the perspective to investigate novel regimes as available laser intensities will be increasing. Experiments have demonstrated, over a wide range of laser and target parameters, the generation of multi-MeV proton and ion beams with unique properties such as ultrashort duration, high brilliance, and low emittance. An overview is given of the state of the art of ion acceleration by laser pulses as well as an outlook on its future development and perspectives. The main features observed in the experiments, the observed scaling with laser and plasma parameters, and the main models used both to interpret experimental data and to suggest new research directions are described.

/pdf/ion-acceleration-by-superintense-laser-plasma-interaction-2jqzeizem7.pdf

Ion acceleration by superintense laser-plasma interaction

Particle-in-cell (PIC) methods have a long history in the study of laser-plasma interactions. Early electromagnetic codes used the Yee staggered grid for field variables combined with a leapfrog EM-field update and the Boris algorithm for particle pushing. The general properties of such schemes are well documented. Modern PIC codes tend to add to these high-order shape functions for particles, Poisson preserving field updates, collisions, ionisation, a hybrid scheme for solid density and high-field QED effects. In addition to these physics packages, the increase in computing power now allows simulations with real mass ratios, full 3D dynamics and multi-speckle interaction. This paper presents a review of the core algorithms used in current laser-plasma specific PIC codes. Also reported are estimates of self-heating rates, convergence of collisional routines and test of ionisation models which are not readily available elsewhere. Having reviewed the status of PIC algorithms we present a summary of recent applications of such codes in laser-plasma physics, concentrating on SRS, short-pulse laser-solid interactions, fast-electron transport, and QED effects.

/pdf/contemporary-particle-in-cell-approach-to-laser-plasma-1hb69lir4e.pdf

Contemporary particle-in-cell approach to laser-plasma modelling

Journal of Physics Condensed Matter: Preface

MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models

High Temperature Equation of State Table Production

A two-dimensional radiation MHD model that includes a self-consistent calculation for non-local thermodynamic equilibrium kinetics and ray-trace radiation transport1 is employed to simulate 65 mm diameter stainless steel double wire array Z machine experiments of 5.0 mg - shot Z1859 and 2.5 mg - shot Z1860 as well as 8 cm diameter, 2.5 mg, argon gas-puff experiments, shots Z2259 - Z2261. Temporal and spatial knowledge of the atomic populations, ion temperatures, and velocities obtained from these calculations allows us to then apply (post-process) detailed multifrequency ray-trace radiation transport, including Doppler effects, to construct time- and axially- or radially-resolved synthetic spectra. Calculated spectra, with and without Doppler effects, for He-like iron and H-like argon near the time of peak emission are compared with experimental data in order to better understand and illustrate time dependent Doppler effects influence on observed spectra.

http://ieeexplore.ieee.org/iel7/7000616/7012143/07012216.pdf

Synthetic time and space resolved spectra including doppler splitting from simulations of stainless steel and argon pinches on Z

NLTE atomic physics model can significantly affect the power requirements and plasma conditions in ignition hohlraums. This is because the emissivity is a significant factor in determining the time dependent coronal temperature of the hot blow‐off plasma filling ignition hohlraums, which, in turn, determines the total energy stored in that coronal plasma at any instant. Here we present best estimates of NLTE emissivity using the SCRAM model, including the range of uncertainty, and compare them with the emissivity of the model used to design NIF ignition hohlraums and set the NIF pulse shape, XSN NLTE. We then present pulse shapes derived from hohlraum simulations using an atomic physics model that approximates the SCRAM emissivities. We discuss the differences in coronal energetics and show how this affects the pulse shape and, in particular, the peak power requirement.

http://absimage.aps.org/image/DPP08/MWS_DPP08-2008-000386.pdf

Effect of NLTE emissivity models on NIF ignition hohlraum power requirements

Bound-bound transitions can occur when localized atomic orbitals are thermally depleted, allowing excitations that would otherwise be forbidden at zero temperature. We predict signatures of bound-bound transitions in x-ray Thomson scattering measurements of laboratory-accessible warm dense conditions. Efficient average-atom models amended to include quasibound states achieve continuity of observables under ionization and agree with time-dependent density functional theory in their prediction of these scattering signatures, which hold compelling diagnostic potential for high-energy-density experiments.

Predictions of bound-bound transition signatures in x-ray Thomson scattering.

Abstract Transport properties of high energy density matter affect the evolution of many systems, ranging from the geodynamo in the Earth’s core, to hydrodynamic instability growth in inertial confinement fusion capsules. Large uncertainties of these properties are present in the warm dense matter regime where both plasma models and condensed matter models become invalid. To overcome this limit, we devise an experimental platform based on x-ray differential heating and time-resolved refraction-enhanced radiography coupled to a deep neural network. We retrieve the first measurement of thermal conductivity of CH and Be in the warm dense matter regime and compare our measurement with the most commonly adopted models. The discrepancies observed are related to the estimation of a correction term from electron-electron collisions. The results necessitate improvement of transport models in the warm dense matter regime and could impact the understanding of the implosion performance for inertial confinement fusion. 

/pdf/thermal-transport-in-warm-dense-matter-revealed-by-2e6m1nck.pdf

Stephanie Hansen

Papers

High Temperature Equation of State Table Production

Synthetic time and space resolved spectra including doppler splitting from simulations of stainless steel and argon pinches on Z

Effect of NLTE emissivity models on NIF ignition hohlraum power requirements

Predictions of bound-bound transition signatures in x-ray Thomson scattering.

Thermal transport in warm dense matter revealed by refraction-enhanced x-ray radiography with a deep-neural-network analysis