Current Status of MHD Simulations for Space Weather

Feng, Xueshang

doi:10.1007/978-981-13-9081-4_1

Cited by 5 publications

(5 citation statements)

References 545 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rectified Linear Unit (ReLU) is a widely used activation function that returns the input value if it is positive and zero otherwise. ReLU is mathematically defined in Equation (7). Since there is a negativity constraint in our modified Ohm's law, we use a rectified linear unit (ReLU) as defined in Equations ( 8) and (9).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Combining Empirical and Physics-Based Models for Solar Wind Prediction

Johnson,

Filali Boubrahimi,

Bahri

et al. 2024

Universe

View full text Add to dashboard Cite

Solar wind modeling is classified into two main types: empirical models and physics-based models, each designed to forecast solar wind properties in various regions of the heliosphere. Empirical models, which are cost-effective, have demonstrated significant accuracy in predicting solar wind at the L1 Lagrange point. On the other hand, physics-based models rely on magnetohydrodynamics (MHD) principles and demand more computational resources. In this research paper, we build upon our recent novel approach that merges empirical and physics-based models. Our recent proposal involves the creation of a new physics-informed neural network that leverages time series data from solar wind predictors to enhance solar wind prediction. This innovative method aims to combine the strengths of both modeling approaches to achieve more accurate and efficient solar wind predictions. In this work, we show the variability of the proposed physics-informed loss across multiple deep learning models. We also study the effect of training the models on different solar cycles on the model’s performance. This work represents the first effort to predict solar wind by integrating deep learning approaches with physics constraints and analyzing the results across three solar cycles. Our findings demonstrate the superiority of our physics-constrained model over other unconstrained deep learning predictive models.

show abstract

Section: Methodsmentioning

confidence: 99%

“…Physics-based solar wind prediction models are based on fundamental physical principles that describe the behavior of the solar wind and its interaction with the Sun's atmosphere (e.g., [7]). These models aim to simulate and forecast the properties and dynamics of the solar wind.…”

Section: Related Workmentioning

confidence: 99%

Combining Empirical and Physics-Based Models for Solar Wind Prediction

Johnson,

Filali Boubrahimi,

Bahri

et al. 2024

Universe

View full text Add to dashboard Cite

show abstract

“…The Magnetohydrodynamic Algorithm outside a Sphere (MAS) code is an in-production MHD model with over 20 years of ongoing development used extensively in Solar physics research [11]- [17]. The code is included in the Corona-Heliosphere (CORHEL) software suite [18], [19] hosted at NASA's Community Coordinated Modeling Center (CCMC) 8 allowing users to generate quasi-steady-state MHD solutions of the corona and heliosphere, as well as simulate solar storms in the form of coronal mass ejections propagating from the Sun to Earth [20], [21]. MAS is written in Fortran (≈ 70, 000 lines) and parallelized with MPI+OpenACC [22].…”

Section: The Mas Solar Mhd Modelmentioning

confidence: 99%

Acceleration of a production Solar MHD code with Fortran standard parallelism: From OpenACC to `do concurrent'

Caplan¹,

M.²,

Linker³

2023

Preprint

View full text Add to dashboard Cite

There is growing interest in using standard language constructs for accelerated computing, avoiding the need for (often vendor-specific) external APIs. These constructs hold the potential to be more portable and much more 'future-proof'. For Fortran codes, the current focus is on the do concurrent (DC) loop. While there have been some successful examples of GPU-acceleration using DC for benchmark and/or small codes, its widespread adoption will require demonstrations of its use in full-size applications. Here, we look at the current capabilities and performance of using DC in a production application called Magnetohydrodynamic Algorithm outside a Sphere (MAS). MAS is a state-of-the-art model for studying coronal and heliospheric dynamics, is over 70,000 lines long, and has previously been ported to GPUs using MPI+OpenACC. We attempt to eliminate as many of its OpenACC directives as possible in favor of DC. We show that using the NVIDIA nvfortran compiler's Fortran 202X preview implementation, unified managed memory, and modified MPI launch methods, we can achieve GPU acceleration across multiple GPUs without using a single OpenACC directive. However, doing so results in a slowdown between 1.25x and 3x. We discuss what future improvements are needed to avoid this loss, and show how we can still retain close to the original code's performance while reducing the number of OpenACC directives by a factor of five.

show abstract

“…Recent advances in the field (see e.g. Green et al 2018;Feng 2020, for recent reviews of the available models) include the EUropean Heliospheric FORecasting Information Asset (EUHFORIA; Pomoell & Poedts 2018), which has been extended to model CMEs using a linear force-free spheromak model (Verbeke et al 2019a). A first test of the predictive capability of this model, limited to non-interacting, single CMEs, has been performed by Scolini et al (2019), who also developed a basic methodological scheme to determine the complete set of CME kinematical, geometrical, and magnetic parameters from remote-sensing observations of CMEs in the solar corona.…”

Section: Introductionmentioning

confidence: 99%

CME–CME Interactions as Sources of CME Geoeffectiveness: The Formation of the Complex Ejecta and Intense Geomagnetic Storm in 2017 Early September

Scolini

Chané

Temmer

et al. 2020

ApJS

123

View full text Add to dashboard Cite

Coronal mass ejections (CMEs) are the primary sources of intense disturbances at Earth, where their geo-effectiveness is largely determined by their dynamic pressure and internal magnetic field, which can be significantly altered during interactions with other CMEs in interplanetary space. We analyse three successive CMEs that erupted from the Sun during September 4-6, 2017, investigating the role of CME-CME interactions as source of the associated intense geomagnetic storm (Dst min = −142 nT on September 7). To quantify the impact of interactions on the (geo-)effectiveness of individual CMEs, we perform global heliospheric simulations with the EUHFORIA model, using observation-based initial parameters with the additional purpose of validating the predictive capabilities of the model for complex CME events. The simulations show that around 0.45 AU, the shock driven by the September 6 CME started compressing a preceding magnetic ejecta formed by the merging of two CMEs launched on September 4, significantly amplifying its B z until a maximum factor of 2.8 around 0.9 AU. The following gradual conversion of magnetic energy into kinetic and thermal components reduced the B z amplification until its almost complete disappearance around 1.8 AU. We conclude that a key factor at the origin of the intense storm triggered by the September 4-6, 2017 CMEs was their arrival at Earth during the phase of maximum B z amplification. Our analysis highlights how the amplification of the magnetic field of individual CMEs in space-time due to interaction processes can be characterised by a growth, a maximum, and a decay phase, suggesting that the time interval between the CME eruptions and their relative speeds are critical factors in determining the resulting impact of complex CMEs at various heliocentric distances (helio-effectiveness).

show abstract

Current Status of MHD Simulations for Space Weather

Cited by 5 publications

References 545 publications

Combining Empirical and Physics-Based Models for Solar Wind Prediction

Combining Empirical and Physics-Based Models for Solar Wind Prediction

Acceleration of a production Solar MHD code with Fortran standard parallelism: From OpenACC to `do concurrent'

CME–CME Interactions as Sources of CME Geoeffectiveness: The Formation of the Complex Ejecta and Intense Geomagnetic Storm in 2017 Early September

Contact Info

Product

Resources

About