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Context.Predicting geomagnetic events starts with an understanding of the Sun-Earth chain phenomena in which (interplanetary) coronal mass ejections (CMEs) play an important role in bringing about intense geomagnetic storms. It is not always straightforward to determine the solar source of an interplanetary coronal mass ejection (ICME) detected at 1 au. Aims.The aim of this study is to test by a magnetohydrodynamic (MHD) simulation the chain of a series of CME events detected from L1 back to the Sun in order to determine the relationship between remote and in situ CMEs. Methods.We analysed both remote-sensing observations and in situ measurements of a well-defined magnetic cloud (MC) detected at L1 occurring on 28 June 2013. The MHD modelling is provided by the 3D MHD European Heliospheric FORecasting Information Asset (EUHFORIA) simulation model. Results.After computing the background solar wind, we tested the trajectories of six CMEs occurring in a time window of five days before a well-defined MC at L1 that may act as the candidate of the MC. We modelled each CME using the cone model. The test involving all the CMEs indicated that the main driver of the well-defined, long-duration MC was a slow CME. For the corresponding MC, we retrieved the arrival time and the observed proton density. Conclusions.EUHFORIA confirms the results obtained in the George Mason data catalogue concerning this chain of events. However, their proposed solar source of the CME is disputable. The slow CME at the origin of the MC could have its solar source in a small, emerging region at the border of a filament channel at latitude and longitude equal to +14 degrees.
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CORHEL-CME: An Interactive Tool For Modeling Solar Eruptions
Abstract Coronal Mass Ejections (CMEs) are immense eruptions of plasma and magnetic fields that are propelled outward from the Sun, sometimes with velocities greater than 2000 km/s. They are responsible for some of the most severe space weather at Earth, including geomagnetic storms and solar energetic particle (SEP) events. We have developed CORHEL-CME, an interactive tool that allows non-expert users to routinely model multiple CMEs in a realistic coronal and heliospheric environment. The tool features a web-based user interface that allows the user to select a time period of interest, and employs Regularized Biot-Savart Law (RBSL) flux ropes to create stable and unstable pre-eruptive configurations within a background global magnetic field. The properties of these configurations can first be explored in a zero-beta magnetohydrodynamic (MHD) model, followed by complete CME simulations in thermodynamic MHD, with propagation out to 1 AU. We describe design features of the interface and computations, including the innovations required to efficiently compute results on practical timescales with moderate computational resources. CORHEL-CME is now implemented at NASA's Community Coordinated Modeling Center (CCMC) using NASA Amazon Web Services (AWS). It will be available to the public in early 2024.
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- Award ID(s):
- 1854790
- PAR ID:
- 10523482
- Publisher / Repository:
- Journal of Physics
- Date Published:
- Journal Name:
- Journal of Physics: Conference Series
- Volume:
- 2742
- Issue:
- 1
- ISSN:
- 1742-6588
- Page Range / eLocation ID:
- 012012
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract We present a transformer model, named DeepHalo, to predict the occurrence of halo coronal mass ejections (CMEs). Our model takes as input an active region (AR) and a profile, where the profile contains a time series of data samples in the AR that are collected 24 hr before the beginning of a day, and predicts whether the AR would produce a halo CME during that day. Each data sample contains physical parameters, or features, derived from photospheric vector magnetic field data taken by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. We survey and match CME events in the Space Weather Database Of Notification, Knowledge, Information and the Large Angle and Spectrometric Coronagraph CME Catalog, and we compile a list of CMEs, including halo CMEs and nonhalo CMEs, associated with ARs in the period between 2010 November and 2023 August. We use the information gathered above to build the labels (positive vs. negative) of the data samples and profiles at hand, where the labels are needed for machine learning. Experimental results show that DeepHalo with a true skill statistic (TSS) score of 0.907 outperforms a closely related long short-term memory network with a TSS score of 0.821. To our knowledge, this is the first time that the transformer model has been used for halo CME prediction.more » « less
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Predictions of coronal mass ejection (CME) propagation and impact in the heliosphere, in either research or operational settings, are usually performed by employing magnetohydrodynamic (MHD) models. Within such simulations, the CME ejecta is often described as a hydrodynamic pulse that lacks an internal magnetic field and is characterized by a spherical geometry – leading to the so-called cone CME model. White-light observations of CMEs in the corona, however, reveal that the morphology of these structures resembles more closely that of a croissant, i.e., exhibiting an elongated cross-section of their front. It follows that, in space weather forecasts, the assumption of a spherical geometry may result in erroneous predictions of CME impacts in the heliosphere in terms of hit/miss and arrival time/speed, especially in the case of flank encounters. A spheroid CME model is expected to provide a more accurate description of the elongated morphology that is often observed in CMEs. In this paper, we describe the implementation and initial validation of the spheroid CME model within the MHD EUropean Heliospheric FORecasting Information Asset (EUHFORIA) code. We perform EUHFORIA simulations of an idealized CME as well as a “real” event to compare the spheroidal model with the traditional cone one. We show how the initial ejecta geometry can lead to substantially different estimates in terms of CME impact, arrival time/speed, and geoeffectiveness, especially with increasing distance to the CME nose.more » « less
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Context.Coronal mass ejections (CMEs) are eruptions of plasma from the Sun that travel through interplanetary space and may encounter Earth. CMEs often enclose a magnetic flux rope (MFR), the orientation of which largely determines the CMEs’ geoeffectiveness. Current operational CME models do not model MFRs, but a number of research ones do, including the Open Solar Physics Rapid Ensemble Information (OSPREI) model. Aims.We report the sensitivity of OSPREI to a range of user-selected photospheric and coronal conditions. Methods.We modeled four separate CMEs observed in situ by Parker Solar Probe (PSP). We varied the input photospheric conditions using four input magnetograms (HMI Synchronic, HMI Synoptic, GONG Synoptic Zero-Point Corrected, and GONG ADAPT). To vary the coronal field reconstruction, we employed the Potential Field Source Surface (PFSS) model and varied its source-surface height in the range 1.5–3.0R⊙with 0.1R⊙increments. Results.We find that both the input magnetogram and PFSS source surface often affect the evolution of the CME as it propagates through the Sun’s corona into interplanetary space, and therefore the accuracy of the MFR prediction compared to in situ data at PSP. There is no obvious best combination of input magnetogram and PFSS source surface height. Conclusions.The OSPREI model is moderately sensitive to the input photospheric and coronal conditions. Based on where the source region of the CME is located on the Sun, there may be best practices when selecting an input magnetogram to use.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1088/1742-6596/2742/1/012012
