Simulation study of CO 2

3D numerical simulations of the interaction of a powerful CO2 laser with hydrogen jets demonstrating the role of ionization in the characteristics of induced wakes are presented. Simulations using SPACE, a parallel relativistic particle-in-cell code, are performed in support of the plasma wakefield accelerator experiments being conducted at the Brookhaven National Laboratory (BNL) Accelerator Test Facility (ATF). A novelty of the SPACE code is its set of efficient atomic physics algorithms that compute ionization and recombination rates on the grid and transfer them to particles. The influence of ionization on the spectrum of the pump laser has been studied for a range of gas densities. Simulations reproduce both Stokes and antiStokes shifts in the spectrum of the pump laser, similar to those observed in experiments in the spectrum of the probe. Good agreement has been achieved with the experiments on the effect of variation in gas density on Stokes/antiStokes intensity. In addition, self-injection and trapping of electrons into the self-modulated wakes have been observed and analyzed. The experimentally validated code SPACE will be used for predictive simulations to guide future experiments at BNL ATF

Shaping trailing beams for beam loading via beam-induced-ionization injection at FACET

International audienceRecent progress in plasma based accelerator technology has demonstrated its ability to deliver high energy (GeV) beams in compact structures (centimeter to meter scale plasmas). Current developments of that technology are oriented toward producing beams with quality and energy spread comparable to those obtained using standard accelerating structures. In plasma based accelerators, the beam energy spread can be improved during the acceleration process through beam loading. To achieve optimum beam loading, the beam has to be shaped such that the superposition of its space charge fields and plasma fields result in a uniform accelerating field. In this work we show how beam-induced-ionization injection can be used to shape and inject a trailing beam suitable for beam loading. Our particle-in-cell numerical simulations done with OSIRIS show the ionization injection of a shaped 340 pC, 13 kA and 3  μm long electron beam accelerated to 900 MeV in less than 3 cm of plasma. The configurations considered numerically were based on the beams and plasmas that have been and will be available at the FACET facility

ECP-WarpX/WarpX: 23.12

<h1>Dependencies</h1> <ul> <li><a href="https://github.com/AMReX-Codes/amrex/tree/23.12">AMReX</a>: <code>23.12</code></li> <li><a href="https://github.com/ECP-WarpX/picsar/tree/23.09">PICSAR</a>-QED: <code>23.09</code></li> <li><a href="https://github.com/picmi-standard/picmi">picmistandard</a>: release <code>0.28.0</code></li> <li><a href="https://github.com/openPMD/openPMD-api">openPMD-api</a>: release <code>0.15.1</code></li> <li>Python: 3.8 - 3.12</li> </ul> <h1>List of PRs merged since the last release</h1> <p>This list was generated with</p> <pre><code class="language-sh">git log 23.11.. --format='- %s' </code></pre> <ul> <li>Release 23.12 (#4469)</li> <li>Add external current handling to Ohm's law solver (#4405)</li> <li>fix preprocessor defs for 1D in two locations (#4465)</li> <li>Bugfix in <code>fields.py</code> <code>mesh()</code> with ghost cells included (#4466)</li> <li>Fix typo in "write_diagnostics_on_restart" (#4463)</li> <li>Make geometry.dims abort message more user-friendly (#4459)</li> <li>New Cache Strategy (#4456)</li> <li>Initial commit (#4460)</li> <li>Set <code>amrex.omp_threads = "nosmt"</code> (#4393)</li> <li>AMReX: Update to <code>development</code> (#4455)</li> <li>Clang-Tidy Cache (#4453)</li> <li>Allow multiple injection sources per species (#4196)</li> <li>Frontier (OLCF): cupy (#4247)</li> <li>add start/end moving step (#4437)</li> <li>Contributing style and conventions additions (#4452)</li> <li>CPU CI: Always Serialize (#4451)</li> <li>Maxlevel user option for external field initialization (#4326)</li> <li>Doc: Fix Typo <code><probe>.integrate = true</code> (#4449)</li> <li>CI: numprocs * numthreads <= 2 (#4450)</li> <li>AMReX/pyAMReX/PICSAR: Weekly Update (#4447)</li> <li>Move AnyFFT.H and FFT wrappers into ablastr (#4005)</li> <li>Clang tidy CI test: add almost all modernize-* checks (#4319)</li> <li>Set the particle fields directly to the constant external fields (#4339)</li> <li>fix minor bug in picmi <code>ParticleDiagnostic</code> (#4442)</li> <li>Make whitespace alignment more consistent (#4440)</li> <li>Add gaussian_parse_momentum_function (#4400)</li> <li>Make the static variable "authors" of the WarpX class a private member of the WarpX class (#4404)</li> <li>Refinement patch parser (#4299)</li> <li>Add python binding to <code>WarpXParticleContainer::sumParticleCharge</code> (#4406)</li> <li>[pre-commit.ci] pre-commit autoupdate (#4433)</li> <li>Add paper using WarpX for laser-driven fusion (#4428)</li> <li>AMReX: Weekly Update (#4431)</li> <li>Fix unused variable with OpenPMD=OFF (#4421)</li> <li>Doc: Laser Pulse Manip. for LPI (#4414)</li> <li>Parallelize scraping (#4418)</li> <li>Remove legacy references to EvolveEM which had been renamed Evolve (#4422)</li> <li>Update AMReX to latest commit (#4423)</li> <li>CI: Unbreak macOS (#4427)</li> <li>AMReX/pyAMReX/PICSAR: Weekly Update (#4417)</li> </ul&gt

ECP-WarpX/WarpX: 24.01

<h1>Dependencies</h1> <ul> <li><a href="https://github.com/AMReX-Codes/amrex/tree/24.01">AMReX</a>: <code>24.01</code></li> <li><a href="https://github.com/ECP-WarpX/picsar/tree/23.09">PICSAR</a>-QED: <code>23.09</code></li> <li><a href="https://github.com/picmi-standard/picmi">picmistandard</a>: release <code>0.28.0</code></li> <li><a href="https://github.com/openPMD/openPMD-api">openPMD-api</a>: release <code>0.15.1</code></li> <li>Python: 3.8 - 3.12</li> </ul> <h1>List of PRs merged since the last release</h1> <p>This list was generated with</p> <pre><code>git log 23.12.. --format='- %s' </code></pre> <ul> <li>Release 24.01 (#4586)</li> <li>Read external fields from file in restarted simulation (#4547)</li> <li>Doc: Clean Example TODOs (#4584)</li> <li>Reduce tolerance for DSMC CI test (#4576)</li> <li>Beam-beam collision example follow-up (#4578)</li> <li>Scale fields by a dimensionless number between 0 and 1 (#4575)</li> <li>Perlmutter: Load <code>gpu</code> Module (#4573)</li> <li>Beam-beam collision example (#4546)</li> <li>Update dsmc and fusion binary collisions (#4572)</li> <li>Apply particle selection to BTDiagnostics (#4570)</li> <li>Update the field probe diagnostic documentation (#4564)</li> <li>Add filters for boundary scraping diagnostics (#4371)</li> <li>Add semi-implicit CI test (#4565)</li> <li>Change the sign of laser particles (#4568)</li> <li>Update explanation of why 2D simulations are not suitable for plasma-wakefield (#4544)</li> <li>Fix default initialization of runtime attributes. (#4508)</li> <li>Implicit electromagnetic solver using Picard iterations (#4071)</li> <li>Update documentation for checksum (#4561)</li> <li>Fix: BeamRelevant 1D, 2D (#4558)</li> <li>Add DSMC module (#4125)</li> <li>Add updated instructions for WarpX on Karolina (#4545)</li> <li>AMReX/pyAMReX/PICSAR: Weekly Update (#4559)</li> <li>Fix reference (#4552)</li> <li>add hybrid-PIC PoP reference to docs (#4551)</li> <li>Clean up doc to improve readability (#4555)</li> <li>Adding user defined keywords in Hybrid PIC Python class to allow for addition of constants when defining functions for resistivity and current. (#4550)</li> <li>WarpXAMReXInit: move include directive from header to cpp file (#4543)</li> <li>AMReX/pyAMReX/PICSAR: Weekly Update (#4541)</li> <li>[pre-commit.ci] pre-commit autoupdate (#4539)</li> <li>Add updated instructions for WarpX on Karolina (#4477)</li> <li>Doc: CUDA 11.7+ (#4538)</li> <li>Spruce up kinetic_fluid_hybrid_model.rst (#4534)</li> <li>Docs: rename and spruce up boundary conditions section (#4537)</li> <li>Spruce up PIC theory section (#4536)</li> <li>Spruce up ml_dataset_training.rst (#4512)</li> <li>Fix CI for ROCm 6.0 (#4527)</li> <li>Documentation: numbered reference formatting (#4528)</li> <li>Spruce up boosted_frame.rst (#4530)</li> <li>Spruce up cold_fluid_model.rst (#4531)</li> <li>Spruce up input_output.rst (#4532)</li> <li>Fix chirp documentation (#4533)</li> <li>Doc: Extend a Simulation Workflow (#4520)</li> <li>Spruce up amr.rst (#4529)</li> <li>WarpXSumGuardCells: move function definitions in cpp file (#4521)</li> <li>Doc: Fix ChecksumAPI <code>autofunction</code> (#4524)</li> <li>Improve documentation for laser chirp (#4525)</li> <li>move function definition to cpp file (#4522)</li> <li>Add ability to run checksum on openPMD files (#4519)</li> <li>Clang-Tidy: readability-qualified-auto (#4507)</li> <li>Clang-Tidy: performance-noexcept-move-constructor (#4504)</li> <li>Bibliography: make author family names appear last (#4506)</li> <li>Doc: Examples Before APIs</li> <li>Doc: Fix Sphinx Warnings</li> <li>Bibliography: improved citations (#4513)</li> <li>Update descriptions of hybrid-PIC examples (#4479)</li> <li>Clang-tidy: enable no-malloc check in clang-tidy CI test (#4518)</li> <li>Clang-Tidy: readability-inconsistent-declaration-parameter-name (#4514)</li> <li>Clang-Tidy: readability-braces-around-statements (#4511)</li> <li>workflow training neural network from warpx data (#4499)</li> <li>AMReX/pyAMReX/PICSAR: Weekly Update (#4503)</li> <li>Use more consistent species types in fusion module (#4480)</li> <li>Clang-tidy: enable readability-duplicate-include check in clang-tidy CI test (#4496)</li> <li>AMReX/pyAMReX/PICSAR: Weekly Update (#4489)</li> <li>Custom class for bibliography style (#4482)</li> <li>[pre-commit.ci] pre-commit autoupdate (#4500)</li> <li>Move external field parameters out of WarpX class (#4441)</li> <li>Tidy-Clang: performance-type-promotion-in-math-fn (#4497)</li> <li>Clang-Tidy CI: Keep Going after Errors (#4491)</li> <li>Clang-Tidy: Update performance and readability (#4492)</li> <li>sqrt -> std::sqrt (#4490)</li> <li>macOS CI: Fix brew installation (#4493)</li> <li>Add <code>latex_theory/allbibs.bib</code> to bibliography list and delete duplicates (#4481)</li> <li>Set alpha mass directly from NIST data (#4478)</li> <li>pybind11: v2.11.1+ (#4473)</li> <li>Fix typos in comments and docs (#4471)</li> <li>Correct on-axis field boundary for RZ (#4464)</li> <li>Rename Depose -> Deposit (#4474)</li> <li>Doc: Streamline Python Input (#4472)</li> <li>macOS CI: export CCACHE_DEPEND=1 (#4475)</li> <li>Docs: Fix Formatting in <code>parameters.rst</code></li> <li>Docs: Fix Many Small Errors & Warnings</li> <li>Doc: Restructure Examples (#4467)</li> <li>Remove brew cache (#4470)</li> </ul&gt

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved