Welcome and organisational topics
Welcome and some organisational aspects
The air shower simulation code CORSIKA has served as a key part of the simulation chain for numerous astroparticle physics experiments over the past decades. Due to retirement of the original developers and the increasingly difficult maintenance of the monolithic Fortran code of CORSIKA, a new air shower simulation framework has been developed over the course of the last years in C++, called CORSIKA 8.Besides the hadronic and muonic component, the electromagnetic component is one of the key constituents of an air shower. The cascade producing the electromagnetic component of an air shower is driven by bremsstrahlung and photoproduction of electron-positron pairs. At ultrahigh energies or in media with large densities, the bremsstrahlung and pair production processes are suppressed by the Landau-Pomeranchuk-Migdal (LPM) effect, which leads to more elongated showers compared to showers without the LPM suppression. Furthermore, photons at higher energies can produce muon pairs or interact hadronically with nucleons in the target medium, producing a muon component in electromagnetic air showers.In this contribution, we compare electromagnetic showers simulated with the latest Fortran version of CORSIKA and CORSIKA 8, which uses the library PROPOSAL for the electromagnetic component. While earlier validations of CORSIKA 8 electromagnetic showers focused on showers of lower energy, the recent implementation of the LPM effect, photo pair production of muons, and of photohadronic interactions allows now to make a physics-complete comparison also at high energies.
CORSIKA 8 is a new framework for air shower simulations implemented in modern C++17, based on past experience with existing codes like CORSIKA 7. The flexible and modular structure of the project allows the development of independent modules that can produce a fully customizable air shower simulation. The radio module in particular is designed to treat the signal propagation and electric field calculation to each antenna in an autonomous and flexible way. It provides the possibility to simulate simultaneously the radio emission calculated with two independent time-domain formalisms, the “Endpoint formalism” as implemented in CoREAS and the “ZHS” algorithm as ported from ZHAireS. Future development for the simulation of radio emission from particle showers in complex scenarios, for example cross-media showers penetrating from air into ice, can build on the existing radio module, re-using the established interfaces.
In this work, we will present the design and implementation of the radio module in CORSIKA 8, and show a direct comparison of radio emission from air showers simulated with CORSIKA 8, CORSIKA 7 and ZHAireS.
The CORSIKA 8 project aims to develop a versatile and modern framework for particle shower simulations that meets the new needs of experiments and addresses the caveats of existing codes. Of particular relevance is the ability to compute particle showers that pass through two or more different media, of varying density, in a single run within a single code. CORSIKA 8 achieves this flexibility by using a volume tree that specifies volume containment, allowing one to quickly query to which medium a point belongs. Thanks to this design we are able to construct very specific environments with different geometries and media. As an example, we demonstrate this new functionality by running particle showers penetrating from air into Antarctic ice and validating them with a combination of the well-established CORSIKA 7 and Geant 4 codes.
AI accelerators have proliferated in data centers in recent years and are now almost ubiquitous. In addition, their computational power and, most importantly, their energy efficiency are up to orders of magnitude higher than that of traditional computing. Over the last years, various methods and optimizations have been tested to use these hybrid systems for simulations in the context of astroparticle physics utilizing CORSIKA.
The main focus of this talk is the propagation of optical, i.e. fluorescence and Cherenkov, photons through low density inhomogeneous media in the context of the next generation CORSIKA8 simulation framework. Different techniques used and approximations, e.g. the atmospheric model, tested during the development will be presented. The trade-off between performance and precision allows the experiment to achieve its physical precision limited to the real resolution of the experiment and not invest power and time in vanishing precision gains. The additional comparison of classical CPU-based simulations with the new methods validates these methods and allows evaluation against a known baseline.
This contribution describes some recent advances in the parallelization of the generation and processing of radio signals emitted by particle showers in CORSIKA 8. CORSIKA 8 is a Monte Carlo simulation framework for modeling ultra-high energy secondary particle cascades in astroparticle physics.
The aspects associated with the generation and processing of radio signals in antennas arrays are reviewed, focusing on the key design opportunities and constraints for deployment of multiple threads on such calculations. The audience is also introduced to Gyges, a lightweight, header-only and flexible multithread self-adaptive scheduler written compliant with C++17 and C++20, which is used to distribute and manage the worker computer threads during the parallel calculations. Finally, performance and scalability measurements are provided and the integration into CORSIKA 8 is commented.
CORSIKA up to version 7 has been the most-used Monte Carlo code for simulating extensive air showers for more than 20 years. Due to its monolithic, Fortran-based software design and hand-optimized code, however, it has become difficult to maintain, adapt to new computing paradigms and extend for more complex simulation needs. These limitations led to the CORSIKA 8 project, which constitutes a complete rewrite of the CORSIKA 7 core functionality in a modern, modular C++ framework. CORSIKA 8 has now reached a state that we consider ``physics-complete'' and a stability that already allows experts to engage in development for specific applications. It already supports the treatment of hadronic interactions with Sibyll 2.3d, QGSJetII-04, EPOS-LHC and Pythia 8.3 and the treatment of the electromagnetic cascade with PROPOSAL 7.6. Particular highlights are the support for multiple interaction media, including cross-media particle showers, and an advanced calculation of the radio emission from particle showers. In this contribution, we discuss the design principles of CORSIKA 8, give an overview of the functionality implemented to date, the validation of its simulation results, and the plans for its further development.
Monte Carlo (MC) generators are a fundamental tool in particle and astroparticle physics. To achieve a high-quality simulation of physical processes involving hadrons, the hadronic interaction model of the generator must be tuned efficiently. The free parameters of MC generators are optimized with the help of experimental data and Bayesian methods.
One area of application for MC generators is the simulation of cosmic-ray induced air showers in the Earth’s atmosphere. Since hadronic interactions have a direct influence on the composition of secondary particles in the shower formations, tuning the parameters of these hadronic models has an impact on crucial observables such as the muon number.
In this talk, studies on the tuning of Monte Carlo generators for cosmic-ray induced air showers are presented.
In this talk I will present a new model for hadron-ion collisions in Pythia8/Angantyr, for generic hadron species. This work also includes a feature to change the hadron species and energies on an event-by-event basis, which is particularly important for applications to hadronic showers. The basic features of the model are tested by comparing to photoproduction data from HERA, UPC data from ATLAS, and pion-carbon scattering data from NA61/SHINE.
The latest propagators are going to be introduced along with signal pulse comparisons between the latest version of C8, C7 and ZHAireS. This presentation should serve as preliminary results for the corresponding ICRC 2023 contribution.
To detect the cosmic neutrino flux at the highest energies, Askaryan radio detectors are being deployed in the polar regions. These detectors use the radio detection technique to cover multi-gigaton detection volumes to probe neutrino interactions in the polar ice. Cosmic ray showers can serve as essential calibration sources for in-ice Askrayan radio detectors. However, if not well understood, radio emissions from cosmic ray showers pose an essential background signal in the neutrino search. The neutrino signal is almost perfectly mimicked by cosmic-ray particle cascades moving from air to ice. We present a simulation framework to model the radio emissions from cosmic-ray showers by combining the in-air and in-ice radio emission frameworks to fully characterize the cosmic-ray radio signal as observed by the in-ice antennas. The framework involves a CoREAS-based code to simulate in-air radio emissions and a GEANT4-based code for in-ice radio emissions from cosmic-ray showers as seen by an in-ice antenna. The cosmic-ray shower particles that reach the ice surface at the end of the CORSIKA 7 simulation are injected into the GEANT4-based shower simulation code that takes the cosmic-ray shower particles and propagates them further into the ice sheet. The CoREAS-based and the GEANT4-based codes have been adapted to account for curved ray paths caused by the exponential refractive index profiles of air and ice. We will also discuss possible ways to port this framework into CORSIKA 8.
If needed, I can do an extended talk about Cherenkov light production.
Code should be available until then in a branch.
Air fluorescence has been usually neglected in current IACTs and wide-angle timing air Cherenkov detectors as the fluorescence light component is emitted isotropically and with a lower light yield than the Cherenkov component. However, next-generation km-scale arrays will register signals from air showers at impact distances where both light components start to be comparable. In order to take into account the fluorescence light in shower reconstruction, we need Monte Carlo simulations. Following the implementation we did in CORSIKA 7, we aim to also develop the emission of air fluorescence in the new CORSIKA 8 framework. As a starting point, we can share the FORTRAN routines we implemented in CORISKA 7 as a stand-alone piece of code. We will discuss the aspects needed to make this implementation possible, such as the tracking of charged particles, corresponding deposited energy, and tabulated atmosphere.
Work done so far
Improvements since last workshop
Remaining issues?
Improvements since the last workshop
State of things
Possible further work
Recently I had a need to run CORSIKA in isolated environment due to its bundling with my legacy code in Python 2.7. To solve this issue I used docker virtualization to build custom CORSIKA docker image and docker-compose for its combination with other services. I would like to share my experience and discuss creation of official C7/C8 docker images provided to community.
Welcome and organisational topics