Rene Widera

Rene Widera
Helmholtz-Zentrum Dresden-Rossendorf | HZDR · Institute of Radiation Physics

About

28
Publications
8,667
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416
Citations

Publications

Publications (28)
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...
Technical Report
Full-text available
Three kernels, Current Deposition (also known as Compute Current), Particle Push (Move and Mark), and Shift Particles are known to be some of the most time-consuming kernels in PIConGPU. The Current Deposition kernel and Particle Push kernel both set up the particle attributes for running any physics simulation with PIConGPU, so it is crucial to im...
Technical Report
Full-text available
This is a technical report that summarizes findings on the analysis of PIConGPU's three most intensive kernels by using NVProf Profiler tool and Summit system at the Oak Ridge National Lab (ORML). The kernels, Current Deposition (also known as Compute Current), Particle Push (Move and Mark), and Shift Particles are known to be some of the biggest k...
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
Quantitative predictions from synthetic radiation diagnostics often have to consider all accelerated particles. For particle-in-cell (PIC) codes, this not only means including all macro-particles but also taking into account the discrete electron distribution associated with them. This paper presents a general form factor formalism that allows to d...
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
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...
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...
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
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...
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...
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...
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...
Article
We show that X-ray optical free-electron lasers (OFELs) can be realized using Traveling-Wave Thomson-Scattering (TWTS). In TWTS pulse front tilted laser pulses are scattered off relativistic electron bunches in a side-scattering geometry. The pulse-front tilt guarantees overlap between laser and electrons over distances in the meter range while bot...
Conference Paper
More and more computationally intensive scientific applications make use of hardware accelerators like general purpose graphics processing units (GPGPUs). Compared to software development for typical multi-core processors their programming is fairly complex and needs hardware specific optimizations to utilize the full computing power. To achieve hi...
Article
The particle-in-cell (PIC) algorithm is one of the most widely used algorithms in computational plasma physics. With the advent of graphical processing units (GPUs), large-scale plasma simulations on inexpensive GPU clusters are in reach. We present an implementation of a fully relativistic plasma PIC algorithm for GPUs based on the NVIDIA CUDA lib...

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Projects

Projects (3)
Project
Test, verify and improve the spectrally resolved far field radiation in PIConGPU
Project
run PIConGPU with all features on x86, power8 and NVIDIA GPUs