Zhenguang Huang

Numerical models are essential for advancing fundamental research in heliophysics and for operational forecasting of space weather events. Open science can accelerate progress, but applying an open science approach to numerical models requires careful consideration; models are not data analysis software and often demand substantial domain expertise, experience, and computational resources to be used correctly. This commentary distills the recommendations from Corti et al. (2026), https://doi.org/10.22541/essoar.176824639.92354528/v2 and proposes a pathway for advancing heliophysics and space weather modeling through open science. Rather than focusing on open science policies and practices, we recommend concrete actions to make models usable by the broader community (open use), increase confidence and transparency throughout the Research‐to‐Operations‐to‐Research (R2O2R) pipeline (open validation), enable collaborative model improvement (open development), and strengthen partnerships (open collaboration). Together, these recommendations address several of the open science challenges experienced by contributing authors in developing, validating, using, and hosting advanced models, as identified during the 2024 Open Science Workshop held at College Park, USA. The recommendations also highlight the importance of a culture of shared responsibility, adherence to best practices, and proper recognition of prior work. The Heliophysics Open Modeling Environment will serve as a platform for modelers and model users to work together, facilitate community modeling, and increase the scientific return on modeling investment.

We present a community‐wide effort to develop a strategy and action plan to advance heliophysics and space weather modeling through open science. While open science has the potential to enhance the quality and pace of scientific discovery, its application to scientific modeling requires more careful consideration regarding open data and open software guidelines, as scientific models differ significantly from data analysis software. We gathered feedback from modeling teams worldwide through a living survey and discussion sessions at the 2024 Open Science Workshop in College Park, USA, and at the 2025 COSPAR ISWAT Working Meeting in Cape Canaveral, USA. We complement these findings with lessons learned from almost 25 years of experience at the Community Coordinated Modeling Center in enabling open use of models. We identify key roadblocks in current open science practices and guidelines and offer recommendations for future progress across four overlapping themes: open use of models and simulation results, open validation, open development, and open collaboration. An essential outcome of the discussion is the need for model developers and model users to speak with a united voice and promote the role of models in future open science efforts. We introduce a new cross‐domain community initiative called the Heliophysics Open Modeling Environment (HOME), which will be integrated as an overarching activity within COSPAR ISWAT. HOME will serve as a platform for modelers and model users to work together, facilitate community modeling, improve the scientific return on modeling investment, and advance understanding, modeling, and forecasting in heliophysics and space weather.

We present a community effort to assess how open science can advance heliophysics and space weather modeling. Open science has the potential to enhance the quality and pace of scientific discovery, but its application to scientific modeling requires more careful consideration with respect to open data and open software guidelines, as complex scientific models are not ordinary software. We gathered feedback from modeling teams worldwide through a living survey and discussion sessions at the Open Science Workshop in College Park, USA, in 2024, and the COSPAR ISWAT Initiative Working Meeting in Cape Canaveral, USA, in 2025. We complement these findings with lessons learned from almost 25 years of experience at the Community Coordinated Modeling Center in enabling open use of models. We identify key roadblocks in current open science practices and guidelines and offer recommendations for future progress. Our findings are organized into four overlapping themes: open use of models and simulation results, open validation, open development, and open collaboration. An essential outcome of the discussion is the need for model developers and users to speak with a united voice and promote the role of models in future open science efforts. We introduce a new cross-domain community initiative called Heliophysics Open Modeling Environment (HOME), which will be integrated as an overarching activity within the COSPAR ISWAT Initiative. HOME will serve as a platform for modelers and model users to work together, facilitate community modeling, improve the scientific return on modeling investment, and advance innovation in heliophysics and space weather.

While humans become more reliant on Earth's space environment, the potential for significant harm from severe space weather continues to grow. As structures from the sun reach Earth's magnetosphere and space environment, they deposit energy that fuels geomagnetic storms. Currently, space weather researchers work to predict the timing and intensity of space weather events, often providing warnings of several days prior to the initiation of a strong geomagnetic storm. Here a new paradigm is presented where, rather than prediction alone, active steps are taken to mitigate the impact of solar wind structures through temporarily modifying Earth's magnetosphere. Global magnetohydrodynamic simulations are used to demonstrate that artificial mass‐loading Earth's dayside magnetosphere can fortify Earth's space environment against strong space weather events. The simulations and supporting analysis use realistic mass‐loading from model spacecraft at geosynchronous orbit to show the validity of the enabling physics as well as technical feasibility with current technology. The results demonstrate that with modern technology, the intensity of a major geomagnetic storm (e.g., polar cap potential, auroral electrojet index) could be actively reduced by 50% or more, protecting technology and human life.

Numerical models of the solar wind and coronal mass ejections (CMEs) utilize photospheric magnetic field observations to prescribe the inner boundary conditions for the plasma solutions. These magnetic field data are available to the community through various observational instruments, prepared via different methodologies and/or flux transport models. The solar wind solution driven by these maps provides the ambient plasma environment into which CMEs travel. Interaction with the surrounding solar wind impacts CME evolution and propagation in the solar corona and inner heliosphere. In this work, we use different input magnetic field maps for the same time period to drive the global Alfvén Wave Solar atmosphere Model. We obtain the ambient solar wind conditions and compare the plasma properties and magnetic morphology in the corona domain to study the influence of the input maps. To understand how the resulting coronal solutions impact CMEs, we launch eruptions described by analytical flux ropes into these data-driven solutions and compare their evolution in the coronal domain (up to 24 R _⊙ radially). The CMEs achieve varying speeds, deceleration rates, propagation directions, mass, and energies while coupling with the background solar wind. We quantify these differences to show that the different input driving maps can significantly impact the simulated CME propagation in the solar wind plasma. This also highlights the importance of understanding the uncertainties associated with data-driven modeling that become increasingly important in operational models and space weather prediction.

On 2022 September 5, a large solar energetic particle (SEP) event was detected by Parker Solar Probe (PSP) and Solar Orbiter (SolO) at heliocentric distances of 0.07 and 0.71 au, respectively. PSP observed an unusual velocity dispersion signature: particles below ∼1 MeV exhibited a normal velocity dispersion, while higher-energy particles displayed an inverse velocity arrival (IVA) feature, with the most energetic particles arriving later than those at lower energies. The maximum energy increased from about 20–30 MeV upstream to over 60 MeV downstream of the shock. The arrival of SEPs at PSP was significantly delayed relative to the expected onset of the eruption. In contrast, SolO detected a typical large SEP event characterized by a regular velocity dispersion at all energies up to 100 MeV. To understand these features, we simulate particle acceleration and transport from the shock to the observers with our newly developed SEP model—Particle ARizona and MIchigan Solver on Advected Nodes. Our results reveal that the IVA and delayed particle onset detected by PSP originate from the time-dependent diffusive shock acceleration processes. After shock passage, PSP’s magnetic connectivity gradually shifted due to its high velocity near perihelion, detecting high-energy SEPs streaming sunward. Conversely, SolO maintained a stable magnetic connection to the strong shock region where efficient acceleration was achieved. These results underscore the importance of spatial and temporal dependence in SEP acceleration at interplanetary shocks and provide new insights to understand SEP variations in the inner heliosphere.

We present an unprecedented simulation of how two large-scale heliospheric transients—a coronal mass ejection (CME) and a corotating stream interaction region—collide, producing a dramatic increase in the complexity of the CME due to formation of mesoscale flux ropes. These structures are captured for the first time by a numerical simulation using high-resolution numerical grids. The circumstances that lead to the formation of these complex structures occur during solar maximum. At the time of the solar maximum taken for this study, 2014 September, the heliospheric current sheet is vertically inclined running over the poles, allowing the CME to impact a preceding slow-fast stream interaction region. The simulation is performed with the Alfvén Wave Solar Atmosphere Model (or AWSoM), with which we initiate a fast CME from active region (AR) 12158 by applying a Gibson–Low magnetic flux rope. Magnetic reconnection within the leading extremity of the CME results in the formation of mesoscale flux ropes, which contain sufficiently strong magnetic fields (∼30 nT) to affect planetary magnetospheres. Finally, we use a tetrahedral configuration of four virtual probes, corresponding to the Space Weather Investigation Frontier mission concept, to show that the mission can uniquely resolve the spatial characteristics and temporal evolution of reconnecting current sheets within the CME, as well as the resulting mesoscale structures.

Slow solar wind is typically characterized as having low Alfvénicity, but the occasional occurrence of highly Alfvénic slow solar wind (HASSW) raises questions about its source regions and evolution. In this work, we conduct a statistical analysis of temperature anisotropy and helium abundance in HASSW using data from the Parker Solar Probe (PSP) within 0.25 au, Helios between 0.3 au and 1 au, and Wind near 1 au. Our findings reveal that HASSW is prevalent close to the Sun, with PSP observations displaying a distinct “U-shaped” Alfvénicity distribution with respect to increasing solar wind speed, unlike the monotonic increase trend seen in Helios and Wind data. This highlights a previously unreported population of unusually low-speed HASSW, which is found in both sub-Alfvénic and super-Alfvénic regimes. The observed decreasing overlap in temperature anisotropy between HASSW and fast solar wind (FSW) with increasing heliocentric distance suggests different underlying heating processes. Additionally, HASSW exhibits two distinct helium abundance populations, particularly evident in PSP data, with generally higher helium abundance compared to less Alfvénic slow solar wind. Moreover, the decreasing overlap in temperature anisotropy versus helium abundance distributions between HASSW and FSW with decreasing radial distance implies that not all HASSW originates from the same source region as FSW.