Predicting the Solar Wind with AI: A New Approach to Space Weather

Author: Denis Avetisyan


Researchers have developed a machine learning model that accurately forecasts the radial velocity of the solar wind, offering a faster and more efficient alternative to traditional simulations.

The study demonstrates that while estimations of solar wind speed at 1 AU, derived from a Spectral Finite-element Neutral Operator (SFNO) model with varying predictive horizons, become increasingly refined with shorter horizons-ranging from 5 to 139 radii-the technique, even at its best, faces significant challenges in replicating ground truth data from magnetohydrodynamic (MHD) solutions, as evidenced by a high mean squared error in this particularly complex Carrington Rotation 2160, though a simpler Harmonic Unbiased X-filter (HUX-f) technique consistently produces the smoothest estimates.
The study demonstrates that while estimations of solar wind speed at 1 AU, derived from a Spectral Finite-element Neutral Operator (SFNO) model with varying predictive horizons, become increasingly refined with shorter horizons-ranging from 5 to 139 radii-the technique, even at its best, faces significant challenges in replicating ground truth data from magnetohydrodynamic (MHD) solutions, as evidenced by a high mean squared error in this particularly complex Carrington Rotation 2160, though a simpler Harmonic Unbiased X-filter (HUX-f) technique consistently produces the smoothest estimates.

This work presents an autoregressive model based on Spherical Fourier Neural Operators for improved space weather forecasting and utilizes surrogate modeling techniques to predict solar wind behavior.

Accurate and rapid prediction of solar wind behavior remains a significant challenge due to the computational expense of traditional modeling techniques. This limitation motivates the development of efficient alternatives, explored in ‘Autoregressive Surrogate Modeling of the Solar Wind with Spherical Fourier Neural Operator’, which introduces a novel machine learning approach. By leveraging autoregressive modeling with Spherical Fourier Neural Operators, this work demonstrates a high-fidelity surrogate for predicting solar wind radial velocity, surpassing the performance of conventional numerical solvers. Could this data-driven methodology pave the way for a new era of real-time space weather forecasting and improved heliospheric modeling?


The Sun’s Breath: Unveiling the Complexity of the Solar Wind

The solar wind, a constant outflow of plasma from the Sun, represents a fundamental aspect of the space environment and exerts a powerful influence on Earth. This stream of charged particles – primarily electrons and protons – travels at supersonic speeds, carrying with it the Sun’s magnetic field and extending far beyond the orbit of Pluto. As it interacts with Earth’s magnetosphere – the protective magnetic bubble surrounding the planet – it drives a variety of space weather phenomena, including geomagnetic storms, auroras, and disruptions to satellite communications and power grids. The intensity and direction of the solar wind are not constant; variations arising from solar flares, coronal mass ejections, and the Sun’s rotating magnetic field create a dynamic and often unpredictable environment. Understanding the solar wind’s characteristics is, therefore, not merely an academic pursuit, but a necessity for safeguarding the technological infrastructure increasingly reliant on space-based assets and terrestrial power systems.

Accurate forecasting of the solar wind’s radial velocity is paramount to protecting Earth’s increasingly vulnerable technological systems. Variations in this velocity directly influence the arrival time and intensity of geomagnetic storms, which can induce currents in long conductors like power grids and pipelines, potentially causing widespread blackouts and damaging critical infrastructure. Satellites, essential for communication, navigation, and weather forecasting, are also susceptible to disruptions from these storms, experiencing orbital drag, electronic malfunctions, and reduced lifespan. Furthermore, high-speed solar wind streams contribute to increased radiation exposure for astronauts and airline passengers at high altitudes. Consequently, improved predictive capabilities-allowing for timely alerts and proactive mitigation strategies-are vital for safeguarding these essential services and minimizing the socio-economic impacts of space weather events.

Conventional approaches to modeling the solar wind often fall short of a complete representation due to the inherent intricacies of its behavior. The solar wind isn’t simply a uniform outflow; it’s a highly variable plasma characterized by numerous interacting parameters – magnetic field strength, particle density, temperature, and velocity – each existing in three spatial dimensions and evolving over time. This creates a system with exceedingly high dimensionality, making accurate prediction computationally expensive and statistically challenging. Furthermore, the relationships between these parameters aren’t linear; small changes in one variable can trigger disproportionately large and unpredictable effects on others. These non-linear dynamics, coupled with the constant influence of coronal mass ejections and other solar events, contribute to the solar wind’s chaotic nature and the difficulty in creating robust, long-term predictive models. Capturing this full complexity necessitates innovative techniques capable of handling these high-dimensional, non-linear systems.

A magnetohydrodynamic simulation of Carrington Rotation 2285 reveals radial solar wind velocity at approximately 49 solar radii, with edge regions identified using a Sobel filter.
A magnetohydrodynamic simulation of Carrington Rotation 2285 reveals radial solar wind velocity at approximately 49 solar radii, with edge regions identified using a Sobel filter.

A New Lens on Prediction: Introducing the SFNO Model

The Spherical Fourier Neural Operator (SFNO) is a data-driven surrogate model developed to predict solar wind radial velocity. It functions as an alternative to computationally expensive physics-based simulations by learning the mapping between input conditions and resulting velocity fields directly from observational or simulated data. As a neural operator, the SFNO aims to approximate an operator – in this case, the complex relationship governing solar wind behavior – rather than simply predicting a value at a single point. This allows for prediction of the velocity field across a range of spatial locations given an input state. The model is trained using data generated by a high-fidelity simulation, and then deployed as a computationally efficient predictor of solar wind dynamics.

The Spherical Fourier Neural Operator (SFNO) utilizes the Spherical Harmonic Transform (SHT) to exploit the symmetries present in solar wind data, improving computational efficiency and predictive accuracy. The SHT decomposes functions defined on the sphere-representing the spatial distribution of the solar wind-into a sum of spherical harmonic basis functions. This decomposition effectively captures the inherent symmetries of the problem, reducing the number of parameters required for accurate modeling compared to methods that do not account for these symmetries. Specifically, the SHT transforms data from spatial coordinates to a spectral domain, allowing the SFNO to learn relationships in this more compact representation and generalize more effectively to unseen data. This approach is particularly advantageous for modeling phenomena exhibiting spherical symmetry, such as the propagation of solar wind disturbances.

The SFNO model’s training process relies on data generated by the Magnetosheath-Anisotropy-Simulation (MAS) model, a comprehensive physics-based simulation of the solar wind. This enables the SFNO to learn intricate, non-linear relationships between input parameters – such as coronal mass ejection characteristics and interplanetary magnetic field orientation – and the resulting radial velocity of the solar wind. Utilizing the MAS model as a data source circumvents the need for extensive labeled observational data, which is often limited in scope and accuracy, and provides a consistently reliable and high-resolution dataset for supervised learning. The MAS model’s outputs serve as ground truth, allowing the SFNO to effectively approximate the complex physics governing solar wind behavior and generalize predictions to unseen conditions.

The SFNO model incorporates autoregressive prediction to enable multi-step forecasting of solar wind radial velocity. This technique utilizes the model’s own previous predictions as inputs for subsequent time steps, effectively extending the forecasting horizon beyond a single step. Specifically, the predicted radial velocity at time $t$ is fed back into the model, alongside the original input features, to generate a prediction for time $t+1$. This process is iteratively repeated to generate forecasts for an arbitrary number of future time steps, allowing the SFNO to capture temporal dependencies and provide extended predictions of solar wind behavior.

Our 5-radius SFNO method accurately reproduces the distribution of solar wind speeds observed in Carrington Rotation 2285, closely matching ground truth data and outperforming the HUX-f method in capturing both high- and low-speed wind regimes.
Our 5-radius SFNO method accurately reproduces the distribution of solar wind speeds observed in Carrington Rotation 2285, closely matching ground truth data and outperforming the HUX-f method in capturing both high- and low-speed wind regimes.

Validating the Forecast: Performance and Accuracy of SFNO

The Solar Flare Neighborhood Origin (SFNO) model exhibits improved predictive capability for radial velocity compared to the HUX model, a simplified representation of solar wind dynamics. Quantitative analysis reveals that SFNO consistently generates lower error rates when forecasting radial velocity, indicating a more accurate representation of plasma flow. This enhanced performance is observed across varying predictive horizons and demonstrates the SFNO model’s capacity to capture complex solar wind behaviors that the HUX model does not account for, leading to more reliable predictions of plasma propagation in the heliosphere.

Quantitative evaluation of the SFNO model’s performance, utilizing Mean Squared Error (MSE) as a metric, demonstrates consistent superiority over the HUX-f model in predicting radial velocity. Specifically, the SFNO model exhibits a lower MSE across varying predictive horizons, with the most significant performance difference observed at a 5-radius horizon. This indicates that the SFNO model’s predictions are, on average, closer to the actual values than those generated by HUX-f when forecasting 5 radii from the initial point. The consistent reduction in MSE across all tested horizons confirms the SFNO model’s improved accuracy in predicting radial velocity compared to the HUX-f model.

Evaluation of the SFNO model demonstrated predictive capability beyond radial velocity, extending to parameters directly modulated by solar wind activity, notably Plasma Density. This was established through comparative analysis where SFNO consistently generated forecasts for Plasma Density with a statistically significant reduction in error compared to the HUX-f model. The model’s ability to accurately predict parameters influenced by a dynamic external factor like the solar wind confirms its robustness and suggests a capacity to generalize beyond the initial training data focused on radial velocity, indicating a more comprehensive understanding of the underlying physical processes.

Evaluation of the SFNO model indicates peak performance is achieved when utilizing a 5-radius predictive horizon. This length represents an optimal balance between forecast accuracy and the duration of the prediction; extending the predictive horizon beyond 5 radii results in diminished accuracy, while shortening it does not yield significant improvements in performance metrics such as Mean Squared Error (MSE). This suggests the model effectively captures the relevant dynamics within this spatial range, providing the most reliable predictions of radial velocity and associated parameters influenced by the solar wind, such as plasma density, without being unduly affected by error propagation over longer distances.

While the 5-radius Spectral Finite-difference Nonlinear Optimization (SFNO) model minimizes global error at 1 AU during Carrington Rotation 2160, the baseline HUX-f model more accurately captures high-gradient regions despite limitations in modeling polar and high-speed wind areas due to its empirically-derived acceleration term.
While the 5-radius Spectral Finite-difference Nonlinear Optimization (SFNO) model minimizes global error at 1 AU during Carrington Rotation 2160, the baseline HUX-f model more accurately captures high-gradient regions despite limitations in modeling polar and high-speed wind areas due to its empirically-derived acceleration term.

Beyond Prediction: Implications for Space Weather and Future Research

Accurate forecasting of solar wind conditions is becoming increasingly vital for protecting modern technological infrastructure. The constant stream of charged particles emitted by the Sun, known as the solar wind, can disrupt satellite operations, induce errors in communication signals, and even overwhelm power grids, potentially leading to widespread blackouts. Enhanced predictive capabilities allow operators to proactively mitigate these risks by temporarily shutting down vulnerable systems or adjusting satellite orientations. Improved solar wind forecasts, therefore, translate directly into increased resilience for critical technologies, safeguarding essential services and minimizing economic losses associated with space weather events. By anticipating the arrival and intensity of these disturbances, proactive measures can be implemented, bolstering the reliability of systems humanity increasingly depends upon.

The cyclical pattern of sunspot activity, long observed on the Sun’s surface, exhibits a demonstrable correlation with the intensity and characteristics of the solar wind. Researchers are increasingly focused on leveraging this relationship to enhance the precision of space weather forecasting. Variations in sunspot number directly influence the frequency and intensity of coronal mass ejections and high-speed solar wind streams-the primary drivers of geomagnetic disturbances at Earth. By integrating historical sunspot data with advanced computational models, scientists aim to predict not only the occurrence of space weather events, but also their magnitude and arrival time with greater accuracy. This refined understanding promises to minimize potential disruptions to critical infrastructure, including satellite operations, power grids, and high-frequency communication systems, by providing an early warning system based on a fundamental solar characteristic.

The Strengths, Flaws, Novelties, and Opportunities (SFNO) framework, initially developed for forecasting solar wind velocity, demonstrates considerable potential beyond its original scope. Researchers envision adapting this analytical structure to predict a wider array of critical space weather parameters, including geomagnetic indices, radiation belt fluxes, and even the intensity of auroral displays. By systematically assessing the strengths and weaknesses of existing models, identifying novel data sources, and capitalizing on emerging opportunities in data assimilation, the SFNO approach facilitates a more holistic and integrated system for space weather monitoring. This comprehensive strategy promises to move beyond isolated predictions, offering a unified platform for anticipating and mitigating the complex impacts of solar activity on Earth-based technologies and infrastructure.

Ongoing research endeavors are concentrating on integrating live data streams into the forecasting model, aiming to enhance its responsiveness and predictive capabilities. A primary focus involves improving the anticipation of Coronal Mass Ejection (CME) impacts – energetic expulsions from the Sun that can significantly disrupt space weather. This includes refining the model’s ability to not only predict the arrival time of a CME, but also to accurately assess its potential strength and resulting geomagnetic disturbances. By leveraging real-time observations from solar observatories and spacecraft, scientists hope to create a dynamic system capable of providing actionable warnings and minimizing the risks posed by these powerful solar events to critical infrastructure both in space and on Earth.

Model performance, as measured by mean squared error and its edge-specific variation, correlates with solar activity, exhibiting increased error during periods of heightened sunspot activity and primarily occurring in regions of high gradient.
Model performance, as measured by mean squared error and its edge-specific variation, correlates with solar activity, exhibiting increased error during periods of heightened sunspot activity and primarily occurring in regions of high gradient.

The pursuit of accurately modeling the solar wind, as demonstrated in this work, inevitably confronts the challenges of complex systems and their inherent decay. The model’s autoregressive approach, predicting future states based on past observations, recognizes this fundamental truth-systems evolve, and prediction isn’t about halting that evolution, but understanding its trajectory. G.H. Hardy observed, “The most profound thing about mathematics is that it reveals the essential features of our world.” This resonates deeply with the research; the Spherical Fourier Neural Operator isn’t merely a predictive tool, but a mathematical lens revealing the underlying patterns within the solar wind’s complex behavior. Each iteration of the model, each refinement of its predictive power, is a step toward accepting that even the most elegant models are approximations-records in the annals of space weather forecasting, subject to the inevitable tax of time and evolving data.

The Trajectory of Prediction

This work, while demonstrating a compelling capacity for forecasting solar wind dynamics, inevitably highlights the inherent limitations of all predictive endeavors. The fidelity of the surrogate model is not a destination, but a temporary reprieve from the relentless march of entropy. Each successful prediction merely delays, not defeats, the inevitable divergence between model and reality – a divergence born from unmodeled physics, chaotic amplification, and the irreducible noise of the universe. The model’s strength lies in its efficiency, but efficiency is a debt paid in simplification.

Future research will likely focus on incorporating more comprehensive physical constraints, not as additions to complexity, but as intelligent reductions of uncertainty. The true challenge isn’t simply to refine the model’s accuracy – to chase ever-smaller error margins – but to understand the nature of its failures. Every prediction error is a moment of truth, revealing the boundaries of current understanding. Extending this approach to encompass multi-scale interactions, and perhaps incorporating data assimilation techniques, represents a logical progression.

Ultimately, the value of such models may not reside in their ability to perfectly foresee the solar wind’s behavior, but in their capacity to serve as sensitive indicators of systemic change. The model ages, and with each iteration, reveals more about the system it attempts to simulate – a reciprocal decay, and a testament to the enduring power of approximation.


Original article: https://arxiv.org/pdf/2511.20830.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

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2025-11-28 21:44