Axel Huebl

Axel Huebl
Lawrence Berkeley National Laboratory | LBL · Accelerator Technology and Applied Physics

Dr. rer. nat. (Physics)

About

58
Publications
14,327
Reads
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729
Citations
Additional affiliations
October 2020 - October 2020
Lawrence Berkeley National Laboratory
Position
  • Developer
Description
  • I am a staff member in the Accelerator Modeling Program in the Accelerator Technology & Applied Physics Division. As the first dedicated Research Software Engineer career role in the division, I research, oversee and participate in the development and integration of particle accelerator, beam (particles and laser) and plasma physics simulation codes on Exascale supercomputers. I am actively involved in advanced particle accelerator research activities and lead selected projects as PI.
July 2019 - September 2020
Lawrence Berkeley National Laboratory
Position
  • PostDoc Position
April 2015 - July 2015
Technische Universität Dresden
Position
  • Research Assistant
Description
  • Teaching the undergraduate laboratory courses.
Education
November 2014 - July 2019
Technische Universität Dresden
Field of study
  • Physics
October 2008 - August 2014
Technische Universität Dresden
Field of study
  • Physics

Publications

Publications (58)
Conference Paper
Full-text available
We present a particle-in-cell simulation of the relativistic Kelvin-Helmholtz Instability (KHI) that for the first time delivers angularly resolved radiation spectra of the particle dynamics during the formation of the KHI. This enables studying the formation of the KHI with unprecedented spatial, angular and spectral resolution. Our results are of...
Conference Paper
Porting applications to new hardware or programming models is a tedious and error prone process. Every help that eases these burdens is saving developer time that can then be invested into the advancement of the application itself instead of preserving the status-quo on a new platform. The Alpaka library defines and implements an abstract hierarchi...
Article
Full-text available
Extreme field gradients intrinsic to relativistic laser-interactions with thin solid targets enable compact MeV proton accelerators with unique bunch characteristics. Yet, direct control of the proton beam profile is usually not possible. Here we present a readily applicable all-optical approach to imprint detailed spatial information from the driv...
Article
Full-text available
Laser-ion acceleration with ultra-short pulse, petawatt-class lasers is dominated by non-thermal, intra-pulse plasma dynamics. The presence of multiple ion species or multiple charge states in targets leads to characteristic modulations and even mono-energetic features, depending on the choice of target material. As spectral signatures of generated...
Article
Full-text available
Radiographic imaging with x-rays and protons is an omnipresent tool in basic research and applications in industry, material science and medical diagnostics. The information contained in both modalities can often be valuable in principle, but difficult to access simultaneously. Laser-driven solid-density plasma-sources deliver both kinds of radiati...
Preprint
Full-text available
Particle accelerators are among the largest, most complex devices. To meet the challenges of increasing energy, intensity, accuracy, compactness, complexity and efficiency, increasingly sophisticated computational tools are required for their design and optimization. It is key that contemporary software take advantage of the latest advances in comp...
Article
Full-text available
Physical scenarios where the electromagnetic fields are so strong that Quantum ElectroDynamics (QED) plays a substantial role are one of the frontiers of contemporary plasma physics research. Investigating those scenarios requires state-of-the-art Particle-In-Cell (PIC) codes able to run on top high-performance computing machines and, at the same t...
Preprint
Full-text available
In physics research particle accelerators are highly valued, and extraordinarily expensive, technical instruments. The high cost of particle accelerators results from the immense lengths required to accelerate particles to high energies, using radio frequency cavities. A current promising field of research, laser-driven particle acceleration has th...
Preprint
Full-text available
Physical scenarios where the electromagnetic fields are so strong that Quantum ElectroDynamics (QED) plays a substantial role are one of the frontiers of contemporary plasma physics research. Investigating those scenarios requires state-of-the-art Particle-In-Cell (PIC) codes able to run on top high-performance computing machines and, at the same t...
Preprint
Full-text available
Modeling plasma accelerators is a computationally challenging task and the quasi-static particle-in-cell algorithm is a method of choice in a wide range of situations. In this work, we present the first performance-portable, quasi-static, three-dimensional particle-in-cell code HiPACE++. By decomposing all the computation of a 3D domain in successi...
Preprint
The applications being developed within the U.S. Exascale Computing Project (ECP) to run on imminent Exascale computers will generate scientific results with unprecedented fidelity and record turn-around time. Many of these codes are based on particle-mesh methods and use advanced algorithms, especially dynamic load-balancing and mesh-refinement, t...
Preprint
This paper aims to create a transition path from file-based IO to streaming-based workflows for scientific applications in an HPC environment. By using the openPMP-api, traditional workflows limited by filesystem bottlenecks can be overcome and flexibly extended for in situ analysis. The openPMD-api is a library for the description of scientific da...
Preprint
Maintaining computational load balance is important to the performant behavior of codes which operate under a distributed computing model. This is especially true for GPU architectures, which can suffer from memory oversubscription if improperly load balanced. We present enhancements to traditional load balancing approaches and explicitly target GP...
Article
Full-text available
Plasma-based accelerators use the strong electromagnetic fields that can be supported by plasmas to accelerate charged particles to high energies. Accelerating field structures in plasma can be generated by powerful laser pulses or charged particle beams. This research field has recently transitioned from involving a few small-scale efforts to the...
Article
Full-text available
The fully electromagnetic particle-in-cell code WarpX is being developed by a team of the U.S. DOE Exascale Computing Project (with additional non-U.S. collaborators on part of the code) to enable the modeling of chains of tens to hundreds of plasma accelerator stages on exascale supercomputers, for future collider designs. The code is combining th...
Preprint
Full-text available
WarpX is a general purpose electromagnetic particle-in-cell code that was originally designed to run on many-core CPU architectures. We describe the strategy followed to allow WarpX to use the GPU-accelerated nodes on OLCF's Summit supercomputer, a strategy we believe will extend to the upcoming machines Frontier and Aurora. We summarize the challe...
Article
Coulomb collisions with background plasma are one source of emittance degradation in plasma accelerators. This paper shows that the emittance growth due to Coulomb collisions can be correctly captured in particle-in-cell simulations, with a proper Monte Carlo binary collision module. The theory of the emittance growth due to Coulomb collisions is e...
Article
Full-text available
With the rapid development of short-pulse intense laser sources, studies of matter under extreme irradiation conditions enter further unexplored regimes. in addition, an application of X-ray free-electron Lasers (XfeLs) delivering intense femtosecond X-ray pulses, allows to investigate sample evolution in iR pump-X-ray probe experiments with an unp...
Article
Full-text available
We present ADIOS 2, the latest version of the Adaptable Input Output (I/O) System. ADIOS 2 addresses scientific data management needs ranging from scalable I/O in supercomputers, to data analysis in personal computer and cloud systems. Version 2 introduces a unified application programming interface (API) that enables seamless data movement through...
Article
Full-text available
The Particle-In-Cell code WarpX is being developed by a team of the U.S. DOE Exascale Computing Project to enable the modeling of chains of tens of plasma accelerators on exascale supercomputers, for future collider designs. The code is combining the latest algorithmic advances (e.g., boosted frame, pseudo-spectral Maxwell solvers) with mesh refine...
Preprint
Full-text available
With the rapid development of short-pulse intense laser sources, studies of matter under extreme irradiation conditions enter further unexplored regimes. In addition, an application of X-ray Free- Electron Lasers (XFELs), delivering intense femtosecond X-ray pulses allows to investigate sample evolution in IR pump - X-ray probe experiments with an...
Article
Full-text available
Compact electron accelerators are paramount to next-generation synchrotron light sources and free-electron lasers, as well as for advanced accelerators at the TeV energy frontier. Recent progress in laser-plasma driven accelerators (LPA) has extended their electron energies to the multi-GeV range and improved beam stability for insertion devices. H...
Preprint
Full-text available
Laser-ion acceleration with ultra-short pulse, PW-class lasers is dominated by non-thermal, intra-pulse plasma dynamics. The presence of multiple ion species or multiple charge states in targets leads to characteristic modulations and even mono-energetic features, depending on the choice of target material. As spectral signatures of generated ion b...
Article
Full-text available
Often, the interpretation of experiments concerning the manipulation of the energy distribution of laser-accelerated ion bunches is complicated by the multitude of competing dynamic processes simultaneously contributing to recorded ion signals. Here we demonstrate experimentally the acceleration of a clean proton bunch. This was achieved with a mic...
Article
Full-text available
We report on recent experimental results deploying a continuous cryogenic hydrogen jet as a debris-free, renewable laser-driven source of pure proton beams generated at the 150 TW ultrashort pulse laser Draco. Efficient proton acceleration reaching cut-off energies of up to 20 MeV with particle numbers exceeding 10⁹ particles per MeV per steradian...
Conference Paper
Full-text available
We present an analysis on optimizing performance of a single C++11 source code using the Alpaka hardware abstraction library. For this we use the general matrix multiplication (GEMM) algorithm in order to show that compilers can optimize Alpaka code effectively when tuning key parameters of the algorithm. We do not intend to rival existing, highly...
Conference Paper
Full-text available
We implement and benchmark parallel I/O methods for the fully-manycore driven particle-in-cell code PIConGPU. Identifying throughput and overall I/O size as a major challenge for applications on today’s and future HPC systems, we present a scaling law characterizing performance bottlenecks in state-of-the-art approaches for data reduction. Conseque...
Article
We theoretically investigate high energy – collimated proton beam with three dimensional particle-in-cell simulations of ultra-short petawatt laser interaction with cryogenic hydrogen target of various shapes. Here we show that under appropriate conditions between the laser and target parameters, the protons are accelerated to high energies mainly...
Article
Full-text available
Laser-plasma wakefield accelerators have seen tremendous progress, now capable of producing quasi-monoenergetic electron beams in the GeV energy range with few-femtoseconds bunch duration. Scaling these accelerators to the nanocoulomb range would yield hundreds of kiloamperes peak current and stimulate the next generation of radiation sources cover...
Article
Full-text available
We report on first commissioning results of the DRACO Petawatt ultra-short pulse laser system implemented at the ELBE center for high power radiation sources of Helmholtz-Zentrum Dresden-Rossendorf. Key parameters of the laser system essential for efficient and reproducible performance of plasma accelerators are presented and discussed with the dem...
Article
For the relativistic Kelvin-Helmholtz instability (KHI), which occurs at shear interfaces between two plasma streams, we report results on the polarized radiation over all observation directions and frequencies emitted by the plasma electrons from ab initio kinetic simulations. We find the polarization of the radiation to provide a clear signature...
Article
Full-text available
We present an analysis on optimizing performance of a single C++11 source code using the Alpaka hardware abstraction library. For this we use the general matrix multiplication (GEMM) algorithm in order to show that compilers can optimize Alpaka code effectively when tuning key parameters of the algorithm. We do not intend to rival existing, highly...
Article
Full-text available
We implement and benchmark parallel I/O methods for the fully-manycore driven particle-in-cell code PIConGPU. Identifying throughput and overall I/O size as a major challenge for applications on today's and future HPC systems, we present a scaling law characterizing performance bottlenecks in state-of-the-art approaches for data reduction. Conseque...
Article
Full-text available
The computation power of supercomputers grows faster than the bandwidth of their storage and network. Especially applications using hardware accelerators like Nvidia GPUs cannot save enough data to be analyzed in a later step. There is a high risk of loosing important scientific information. We introduce the in situ template library ISAAC which ena...
Code
PIConGPU is a fully relativistic, many GPGPU, 3D3V particle-in-cell (PIC) code. The Particle-in-Cell algorithm is a central tool in plasma physics. It describes the dynamics of a plasma by computing the motion of electrons and ions in the plasma based on Maxwell’s equations. This release of PIConGPU, providing ”beta” status for users, implements fu...
Article
Full-text available
Realistic simulations of experiments at large scale photon facilities, such as optical laser laboratories, synchrotrons, and free electron lasers, are of vital importance for the successful preparation, execution, and analysis of these experiments investigating ever more complex physical systems, e.g. biomolecules, complex materials, and ultra-shor...
Conference Paper
With the appearance of the heterogeneous platform OpenPower, many-core accelerator devices have been coupled with Power host processors for the first time. Towards utilizing their full potential, it is worth investigating performance portable algorithms that allow to choose the best-fitting hardware for each domain-specific compute task. Suiting ev...
Article
Full-text available
Porting applications to new hardware or programming models is a tedious and error prone process. Every help that eases these burdens is saving developer time that can then be invested into the advancement of the application itself instead of preserving the status-quo on a new platform. The Alpaka library defines and implements an abstract hierarchi...
Code
This is the archive containing the software used for evaluations in the publication "Performance-Portable Many-Core Plasma Simulations: Porting PIConGPU to OpenPower and Beyond" submitted to the international workshop on OpenPOWER for HPC 2016. The archive has the following content: PIConGPU Kelvin-Helmholtz Simulation code (picongpu-alpaka/): Remo...
Data
This releases fixes a potential deadlock encountered during checkpoints and initialization. Furthermore, we forgot to highlight that the 0.2.0 release also included a QED synchrotron emission scheme (based on the review in A. Gonoskov et al., PRE 92, 2015). Please refer to our CHANGELOG.md for a full list of features, fixes and user interface chang...
Thesis
Full-text available
Laser-driven plasma wakefield accelerators provide accelerating electric fields orders of magnitude higher compared to conventional accelerators. Towards the generation of quasi-monoenergetic, multi-gigaelectronvolt electron beams, a precise control in the femtosecond time scale of the injection of electrons is needed. In this diploma thesis a new...
Article
Full-text available
Emerging new technologies in plasma simulations allow tracking billions of particles while computing their radiative spectra. We present a visualization of the relativistic Kelvin-Helmholtz Instability from a simulation performed with the fully relativistic particle-in-cell code PIConGPU powered by 18,000 GPUs on the USA's fastest supercomputer Tit...
Conference Paper
Full-text available
We present a self-consistent method to compute angularly resolved far-field spectra for both coherent and incoherent radiation which enables unprecedented quantitative predictions by taking into account emissions from all ∼10^10 electrons simulated in PIC codes for hundreds to thousands of directions and frequencies. This is applied to predicting t...
Code
That's our our open alpha release. The alpha release is developer and power user release only! Users should wait for our beta release!
Article
The particle-in-cell code PIConGPU provides the feature of calculating angular resolved radiation spectra in the far field based on Liénard─Wiechert potentials for all macroparticles of a plasma simulation. In order to verify the physics of our code we present a series of physics test scenarios, which compare numerical results to analytic solutions...
Technical Report
Full-text available
Proceedings 2010, JSC Guest Student Programme on Scientific Computing Online Version available at: http://www.fz-juelich.de/ias/jsc/EN/Career/Gueststudentprogramme/Previous_years/2010/_node.html

Projects

Projects (3)
Project
Test, verify and improve the spectrally resolved far field radiation in PIConGPU
Project
Atomic processes in laser-driven ion acceleration are currently only crudely described on the time, energy and density scales necessary for predictive simulations. I am using the immense computer power we got from porting the particle-in-cell code PIConGPU to manycore architectures to model those processes more precisely.