arXiv subjects

Teresa Nieves-Chinchilla

Publications and source records attributed to Teresa Nieves-Chinchilla.

At least 19 recordsLinked to original sources

arXiv2026

Understanding the Complex Morphology of a Coronal Mass Ejection. III: How to Create a Severe Geomagnetic Storm

On April 21, 2023, a complex filament eruption produced an Earth-directed coronal mass ejection (CME) that triggered the first severe geomagnetic storm of solar cycle 25. The primary objective of this work is to understand the physical origin of the severe impact of this CME on Earth. We explore the CME's complex morphology by simulating the eruption using the thermodynamic magnetohydrodynamic (MHD) model CORHEL-CME. We model the pre-eruptive structure as two intertwined magnetic flux ropes and validate the early evolution of the event by comparing synthetic observables generated from the model with extreme-ultraviolet and white-light observations. We then compare the simulated CME structure with in situ measurements. From our analysis, we conclude that the CME merged with a stream interaction region (SIR) before reaching Earth. This interaction compressed the CME sheath, producing a sustained negative $B_n$ component that, together with the associated enhancement in solar wind density and velocity, triggered the geomagnetic storm. The internal configuration of the magnetic flux rope, which also maintained a sustained southward component during its propagation toward Earth, intensified the storm to severe levels. This model-data comparison underscores the power of using MHD simulations, when validated by multi-viewpoint observations, to reveal hidden dynamical processes and improve the understanding and prediction of space weather impacts.

astro-ph.SR↗

arXiv2026

Understanding the complex morphology of a CME II: how pre-eruptive conditions shape CME evolution

The morphology and heliospheric impact of coronal mass ejections (CMEs) are strongly shaped by their preeruptive magnetic configuration and surrounding coronal environment, yet these influences remain difficult to constrain observationally. We analyze a complex CME that erupted on 2024 October 26 using multiviewpoint remote sensing observations and in situ measurements. Using the physics based CORHELCME magnetohydrodynamic model, we test multiple physically plausible realizations of the preeruptive magnetic flux rope (MFR) and background magnetic field, using agreement with the observed evolution as a constraint on the CMEs initial state. We find that modest changes in MFR footpoint location and force balance lead to substantially different coronal trajectories, enabling rapid discrimination among candidate initial states. While several configurations reproduce the CMEs large scale propagation, realistic small scale morphology is achieved only when a near dated background magnetic field is employed. The resulting simulation reproduces key morphologies observed from three viewpoints without fine tuning, indicating that the inferred preeruptive configuration represents a robust, global solution and provides a physically consistent interpretation of their magnetic origin. Comparison with in situ shock detections highlights the role of CME solar wind interactions in shaping heliospheric signatures, though shock arrival times remain uncertain at the 11 hr level. These results demonstrate that data informed, physics based modeling can meaningfully constrain CME preeruptive conditions and bridge remote and in situ observations, while emphasizing the need for timely magnetic field measurements to improve predictive capability.

astro-ph.SR↗

arXiv2026

Simulated Operational Testing of the Prototype Implementation of the SOFIE Model: The 2025 Space Weather Prediction Testbed Exercise

The CLEAR Space Weather Center of Excellence's solar energetic particle (SEP) model, SOlar wind with FIeld lines and Energetic particles (SOFIE), was run and evaluated on-site during the Space Weather Prediction Testbed (SWPT) exercise at the National Oceanic and Atmospheric Administration's Space Weather Prediction Center (NOAA/SWPC) in May 2025. As a physics-based SEP model, SOFIE simulates the acceleration and transport of energetic particles by the coronal mass ejection (CME)-driven shock in the solar corona and inner heliosphere, and has been validated against historical events. However, questions remain regarding whether a physics-based model, traditionally considered computationally expensive, could meet operational needs. The SWPT exercise offered a valuable opportunity to evaluate SOFIE under simulated operational conditions. On-site interactive feedback from SWPC forecasters, Space Radiation Analysis Group (SRAG) console operators, Community Coordinated Modeling Center (CCMC) personnel, and Moon-to-Mars Space Weather Analysis Office (M2M SWAO) analysts led to significant strategic improvements in the model configuration. The simulation grid was optimized by combining a coarser background grid with higher-resolution regions along the CME path and toward Earth, reducing computational cost without compromising accuracy. In this work, we present the simulated operational performance of SOFIE and its capability to predict SEP fluxes significantly faster than real time. During the SWPT exercise, SOFIE completed a 4-day SEP simulation within 5 hours using 1,000 central processing unit cores, although the earliest SEP forecast was obtained a few hours after CME onset. This marks a milestone in demonstrating SOFIE's operational usefulness and robustness to support future human space exploration.

astro-ph.SR↗

arXiv2025

Magnetic interaction analysis of multiple interplanetary coronal mass ejections leading to a historic geomagnetic storm in May 2024

Interplanetary coronal mass ejections (ICMEs), the large-scale eruptive phenomena capable of shedding a huge amount of solar magnetic helicity and energy are potential in driving strong geomagnetic storms. They complexly evolve while preceded and followed by other large-scale structures e.g. ICMEs. Magnetic interaction among multiple ICMEs may result intense and long-lived geomagnetic storms. Our aim is to understand the reason of substantial changes in the geoeffectivity of two meso-scale separated counterparts of a complex solar wind structure through investigating their magnetic content e.g. helicity, energy and magnetic interaction among multiple ICMEs. We utilized the insitu observations of solar wind from Wind and Solar Terrestrial Relations Observatory-A (STA) spacecraft during the strongest geomagnetic storm period in past two decades on May 10-11, 2024 and heliospheric imagers onboard STA. Our investigation confirms complex interactions among five ICMEs resulting in distinct counterparts within a coalescing large-scale structure. These counterparts possess substantially different magnetic contents. We conclude that the complex counterpart resulted from the interaction among common-origin ICMEs observed by STA, favorably orientated for magnetic reconnection, had 1.6 and 2.8 times higher total magnetic energy and helicity, respectively, than the counterpart containing a left-handed filament-origin ICME observed by Wind. The left-handed ICME non-favorably oriented for magnetic reconnection with the surrounding right-handed, common-origin ICMEs. Therefore, two medium-separated counterparts despite belonging to a common solar wind structure, were potential to lead different geoeffectivity. This ultimately challenges space weather predictions based on early observations.

astro-ph.SR↗

arXiv2025

Understanding the complex morphology of a CME: multi-view analysis and numerical modeling

Although all coronal mass ejections (CMEs) that propagate into the heliosphere should contain a magnetic flux rope (MFR) component, the majority do not exhibit the expected white-light MFR morphology of a leading edge plus cavity. This different appearance could be the result of distortion of the internal magnetic structure, merging with other structures, or simply projection effects. These factors complicate the interpretation of CMEs. This complexity is exemplified by a CME observed on 28 March 2022. The event originated from a single eruption, evolving as a textbook CME in the low corona but appearing as a complex two-MFR structure in white-light observations. Why? To answer this question, we performed a multi-view data and modeling analysis to describe the CME coronal evolution. The thermodynamic MHD model, CORHEL-CME, helps reveal the magnetic configuration of this CME and also reveals that the ambient field plays a crucial role in shaping the complex structure of the CME during early evolution. Our research underscores the importance of integrating multiview observations with physics-based models to gain a deeper insight into the development of complex CMEs.

astro-ph.SR↗

arXiv2025

Modeling Polarized Radio Sounding Observations of a Coronal Mass Ejection

Coronal Mass Ejections (CMEs) evolve significantly as they propagate from the Sun to the Earth, so remote observations of their changes in speed, strength of the magnetic field, density, and overall structure are critical for predicting their arrival time and geoeffectiveness. Radio line-of-sight observations of Faraday rotation and Total Electron Content combined with white-light observations enables the measurement of these properties with careful analyses. This paper describes the analysis techniques and evaluates their accuracy with regard to measuring a CME's complex evolving structure and speed. The approach utilizes the layout of the Faraday effect tracker of coronal and heliospheric structures (FETCH), a purely space-based instrument concept, with Alfven Wave Solar atmosphere Model (AWSoM) simulations as input for evaluating these radio-based measures. Focusing on density and velocity/speed, we find that in-situ measurements of CME properties observe similar but different aspects of the distinct CME structure. The AWSoM model suggests that Faraday rotation may be a more sensitive measure of structure than Total Electron Content (TEC). Finally, we discuss the difficulty the simulation reveals in determining the trailing edge location of a magnetic flux rope.

astro-ph.IM↗

arXiv2024

Deciphering the Evolution of Thermodynamic Properties and their Connection to the Global Kinematics of High-Speed Coronal Mass Ejections Using FRIS Model

Most earlier studies have been limited to estimating the kinematic evolution of coronal mass ejections (CMEs), and only limited efforts have been made to investigate their thermodynamic evolution. We focus on the interplay of the thermal properties of CMEs with their observed global kinematics. We implement the Flux rope Internal State (FRIS) model to estimate variations in the polytropic index, heating rate per unit mass, temperature, pressure, and various internal forces. The model incorporates inputs of 3D kinematics obtained from the Graduated Cylindrical Shell (GCS) model. In our study, we chose nine fast-speed CMEs from 2010 to 2012. Our investigation elucidates that the selected fast-speed CMEs show a heat-release phase at the beginning, followed by a heat-absorption phase with a near-isothermal state in their later propagation phase. The thermal state transition, from heat release to heat absorption, occurs at around 3($\pm$0.3) to 7($\pm$0.7) $R_\odot$ for different CMEs. We found that the CMEs with higher expansion speeds experience a less pronounced sharp temperature decrease before gaining a near-isothermal state. The differential emission measurement (DEM) analysis findings, using multi-wavelength observation from SDO/AIA, also show a heat release state of CMEs at lower coronal heights. We also find the dominant internal forces influencing CME radial expansion at varying distances from the Sun. Our study shows the need to characterize the internal thermodynamic properties of CMEs better in both observational and modeling studies, offering insights for refining assumptions of a constant value of the polytropic index during the evolution of CMEs.

astro-ph.SR↗

arXiv2024

Classifying different types of solar wind plasma with uncertainty estimations using machine learning

Decades of in-situ solar wind measurements have clearly established the variation of solar wind physical parameters. These variable parameters have been used to classify the solar wind magnetized plasma into different types leading to several classification schemes being developed. These classification schemes, while useful for understanding the solar wind originating processes at the Sun and early detection of space weather events, have left open questions regarding which physical parameters are most useful for classification and how recent advances in our understanding of solar wind transients impact classification. In this work, we use neural networks trained with different solar wind magnetic and plasma characteristics to automatically classify the solar wind in coronal hole, streamer belt, sector reversal and solar transients such as coronal mass ejections comprised of both magnetic obstacles and sheaths. Furthermore, our work demonstrates how probabilistic neural networks can enhance the classification by including a measure of prediction uncertainty. Our work also provides a ranking of the parameters that lead to an improved classification scheme with ~96% accuracy. Our new scheme paves the way for incorporating uncertainty estimates into space weather forecasting with the potential to be implemented on real-time solar wind data.

astro-ph.SR↗

arXiv2024

Flux rope modeling of the 2022 Sep 5 CME observed by Parker Solar Probe and Solar Orbiter from 0.07 to 0.69 au

As both Parker Solar Probe (PSP) and Solar Orbiter (SolO) reach heliocentric distances closer to the Sun, they present an exciting opportunity to study the structure of CMEs in the inner heliosphere. We present an analysis of the global flux rope structure of the 2022 September 5 CME event that impacted PSP at a heliocentric distance of only 0.07 au and SolO at 0.69 au. We compare in situ measurements at PSP and SolO to determine global and local expansion measures, finding a good agreement between magnetic field relationships with heliocentric distance, but significant differences with respect to flux rope size. We use PSP/WISPR images as input to the ELEvoHI model, providing a direct link between remote and in situ observations; we find a large discrepancy between the resulting modeled arrival times, suggesting that the underlying model assumptions may not be suitable when using data obtained close to the Sun, where the drag regime is markedly different in comparison to larger heliocentric distances. Finally, we fit the SolO/MAG and PSP/FIELDS data independently with the 3DCORE model and find that many parameters are consistent between spacecraft, however, challenges are apparent when reconstructing a global 3D structure that aligns with arrival times at PSP and Solar Orbiter, likely due to the large radial and longitudinal separations between spacecraft. From our model results, it is clear the solar wind background speed and drag regime strongly affect the modeled expansion and propagation of CMEs and need to be taken into consideration.

physics.space-ph↗

arXiv2024

Distorted Magnetic Flux Ropes within Interplanetary Coronal Mass Ejections

Magnetic flux ropes within interplanetary coronal mass ejections are often characterized as simplistic cylindrical or toroidal tubes with field lines that twist around the cylinder or torus axis. Recent multi-point observations suggest that the overall geometry of these large-scale structures may be significantly more complex, so that the contemporary modeling approaches would be, in some cases, insufficient to properly understand the global structure of any interplanetary coronal mass ejection. In an attempt to partially rectify this issue, we have developed a novel magnetic flux rope model that allows for the description of arbitrary distortions of the cross-section or deformation of the magnetic axis. The distorted magnetic flux rope model is a fully analytic flux rope model, that can be used to describe significantly more complex geometries and is numerically efficient enough to be used for large ensemble simulations. To demonstrate the usefulness of our model, we focus on a specific implementation of our model and apply it to an ICME event that was observed \textit{in situ} on 2023 April 23 at the L1 point by the Wind spacecraft and also by the STEREO-A spacecraft that was $10.2^\circ$ further east and $0.9^\circ$ south in heliographic coordinates. We demonstrate that our model can accurately reconstruct each observation individual and also gives a fair reconstruction of both events simultaneously using a multi-point reconstruction approach, which results in a geometry that is not fully constistent with a cylindrical or toroidal approximation.

astro-ph.SR↗

arXiv2024

Automatic detection of large-scale flux ropes and their geoeffectiveness with a machine learning approach

Detecting large-scale flux ropes (FRs) embedded in interplanetary coronal mass ejections (ICMEs) and assessing their geoeffectiveness are essential since they can drive severe space weather. At 1 au, these FRs have an average duration of 1 day. Their most common magnetic features are large, smoothly rotating magnetic fields. Their manual detection has become a relatively common practice over decades, although visual detection can be time-consuming and subject to observer bias. Our study proposes a pipeline that utilizes two supervised binary-classification machine learning (ML) models trained with solar wind magnetic properties to automatically detect large-scale FRs and additionally determine their geoeffectiveness. The first model is used to generate a list of auto-detected FRs. Using the properties of southward magnetic field the second model determines the geoeffectiveness of FRs. Our method identifies 88.6\% and 80\% large-scale ICMEs (duration $\ge 1$ day) observed at 1 au by Wind and Sun Earth Connection Coronal and Heliospheric Investigation (STEREO) mission, respectively. While testing with a continuous solar wind data obtained from Wind, our pipeline detected 56 of the 64 large-scale ICMEs during 2008 - 2014 period (recall= 0.875) but many false positives (precision= 0.56) as we do not take into account any additional solar wind properties than the magnetic properties. We found an accuracy of 0.88 when estimating the geoeffectiveness of the auto-detected FRs using our method. Thus, in space weather now-casting and forecasting at L1 or any planetary missions, our pipeline can be utilized to offer a first-order detection of large-scale FRs and geoeffectiveness.

astro-ph.SR↗

arXiv2024

A Survey of Coronal Mass Ejections Measured In Situ by Parker Solar Probe During 2018-2022

We present a statistical investigation of the radial evolution of 28 interplanetary coronal mass ejections (ICMEs), measured in situ by the Parker Solar Probe (PSP) spacecraft from 2018 October to 2022 August. First, by analyzing the radial distribution of ICME classification based on magnetic hodograms, we find that coherent configurations are more likely to be observed close to the Sun. In contrast, more complex configurations are observed farther out. We also notice that the post-ICME magnetic field is more impacted following an ICME passage at larger heliocentric distances. Second, with a multi-linear robust regression, we derive a slower magnetic ejecta (ME) expansion rate within 1~au compared to previous statistical estimates. Then, investigating the magnetic field fluctuations within ICME sheaths, we see that these fluctuations are strongly coupled to the relative magnetic field strength gradient from the upstream solar wind to the ME. Third, we identify ME expansion as an important factor in forming sheaths. Finally, we determine the distortion parameter (DiP) which is a measure of magnetic field asymmetry in an ME. We discover lower overall asymmetries within MEs. We reveal that even for expanding MEs, the time duration over which an ME is sampled does not correlate with DiP values, indicating that the aging effect is not the sole contributor to the observed ME asymmetries.

physics.space-ph↗

arXiv2024

On the Mesoscale Structure of CMEs at Mercury's Orbit: BepiColombo and Parker Solar Probe Observations

On 2022 February 15, an impressive filament eruption was observed off the solar eastern limb from three remote-sensing viewpoints, namely Earth, STEREO-A, and Solar Orbiter. In addition to representing the most-distant observed filament at extreme ultraviolet wavelengths -- captured by Solar Orbiter's field of view extending to above 6 $R_{\odot}$ -- this event was also associated with the release of a fast ($\sim$2200 km$\cdot$s$^{-1}$) coronal mass ejection (CME) that was directed towards BepiColombo and Parker Solar Probe. These two probes were separated by 2$^{\circ}$ in latitude, 4$^{\circ}$ in longitude, and 0.03 au in radial distance around the time of the CME-driven shock arrival in situ. The relative proximity of the two probes to each other and to the Sun ($\sim$0.35 au) allows us to study the mesoscale structure of CMEs at Mercury's orbit for the first time. We analyse similarities and differences in the main CME-related structures measured at the two locations, namely the interplanetary shock, the sheath region, and the magnetic ejecta. We find that, despite the separation between the two spacecraft being well within the typical uncertainties associated with determination of CME geometric parameters from remote-sensing observations, the two sets of in-situ measurements display some profound differences that make understanding of the overall 3D CME structure particularly challenging. Finally, we discuss our findings within the context of space weather at Mercury's distances and in terms of the need to investigate solar transients via spacecraft constellations with small separations, which has been gaining significant attention during recent years.

astro-ph.SR↗

arXiv2023

Kilometric type II radio emissions in Wind/WAVES TNR data and association with interplanetary structures near Earth

Type II radio bursts arise as a consequence of shocks typically driven by coronal mass ejections (CMEs). When these shocks propagate outward from the Sun, their associated radio emissions drift down in frequency as excited particles emit at the local plasma frequency, creating the usual Type II patterns. In this work, we use dynamic spectra from the Wind/WAVES Thermal Noise Receiver (TNR) to identify Type II radio emissions in the kilometric wavelength range (kmTIIs, f < 300 kHz) between 1 January 2000 and 31 December 2012, i.e. over a solar cycle. We identified 134 kmTII events and compiled various characteristics for each of them. Of particular importance is the finding of 45 kmTII events not reported by the official Wind/WAVES catalog (based on RAD1 and RAD2 data). We search for associations with interplanetary structures and analyze their main characteristics, in order to reveal distinctive attributes that may correlate with the occurrence of kmTII emission. We find that the fraction of interplanetary coronal mass ejections (ICMEs) classified as magnetic clouds (MCs) that are associated with kmTIIs is roughly similar to that of MCs not associated with kmTIIs. Conversely, the fraction of ICMEs with bidirectional electrons is significantly larger for those ICMEs associated with kmTIIs (74% vs. 48%). Likewise, ICMEs associated with kmTIIs are on average 23% faster. The disturbance storm time (DsT) mean value is almost twice as large for kmTII-associated ICMEs, indicating that they tend to produce intense geomagnetic storms. In addition, the proportion of ICMEs producing moderate to intense geomagnetic storms is twice as large for the kmTII-associated ICMEs. After this investigation, TNR data prove to be valuable not only as complementary data for the analysis of kmTII events but also for forecasting the arrival of shocks at Earth.

astro-ph.SR↗

arXiv2023

New Observations Needed to Advance Our Understanding of Coronal Mass Ejections

Coronal mass ejections (CMEs) are large eruptions from the Sun that propagate through the heliosphere after launch. Observational studies of these transient phenomena are usually based on 2D images of the Sun, corona, and heliosphere (remote-sensing data), as well as magnetic field, plasma, and particle samples along a 1D spacecraft trajectory (in-situ data). Given the large scales involved and the 3D nature of CMEs, such measurements are generally insufficient to build a comprehensive picture, especially in terms of local variations and overall geometry of the whole structure. This White Paper aims to address this issue by identifying the data sets and observational priorities that are needed to effectively advance our current understanding of the structure and evolution of CMEs, in both the remote-sensing and in-situ regimes. It also provides an outlook of possible missions and instruments that may yield significant improvements into the subject.

astro-ph.IM↗

arXiv2023

Statistical Analysis of Interplanetary Shocks from Mercury to Jupiter

In situ observations of interplanetary (IP) coronal mass ejections (ICMEs) and IP shocks are important to study as they are the main components of the solar activity. Hundreds of IP shocks have been detected by various space missions at different times and heliocentric distances. Some of these are followed by clearly identified drivers, while some others are not. In this study, we carry out a statistical analysis of the distributions of plasma and magnetic parameters of the IP shocks recorded at various distances to the Sun. We classify the shocks according to the heliocentric distance, namely from 0.29 to 0.99 AU (Helios-1/2); near 1 AU (Wind, ACE and STEREO-A/B); and from 1.35 to 5.4 AU (Ulysses). We also differentiate the IP shocks into two populations, those with a detected ICME and those without one. We find, as expected, that there are no significant differences in the results from spacecraft positioned at 1 AU. Moreover, the distributions of shock parameters, as well as the shock normal have no significant variations with the heliocentric distance. Additionally, we investigate how the number of shocks associated to stream-interaction regions (SIRs) increases with distance in proportion of ICME/shocks. From 1 to 5 AU, SIRs/ shock occurrence increases slightly from 21% to 34%, in contrast ICME/shocks occurrence decreases from 47% to 17%. We find also indication of an asymmetry induced by the Parker spiral for SIRs and none for ICMEs.

astro-ph.SR↗

arXiv2022

Deep Learning for Space Weather Prediction: Bridging the Gap between Heliophysics Data and Theory

Traditionally, data analysis and theory have been viewed as separate disciplines, each feeding into fundamentally different types of models. Modern deep learning technology is beginning to unify these two disciplines and will produce a new class of predictively powerful space weather models that combine the physical insights gained by data and theory. We call on NASA to invest in the research and infrastructure necessary for the heliophysics' community to take advantage of these advances.

astro-ph.IM↗

arXiv2022

Writhed Analytical Magnetic Flux Rope Model

Observations of magnetic clouds, within interplanetary coronal mass ejections (ICMEs), are often well described by flux rope models. Most of these assume either a cylindrical or toroidal geometry. In some cases, these models are also capable of accounting for non-axisymmetric crosssections but they generally all assume axial invariance. It can be expected that any ICME, and its flux rope, will be deformed along its axis due to influences such as the solar wind. In this work, we aim to develop a writhed analytical magnetic flux rope model which would allow us to analytically describe a flux rope structure with varying curvature and torsion so that we are no longer constrained to a cylindrical or toroidal geometry. In this first iteration of our model we will solely focus on a circular cross-section of constant size. We describe our flux rope geometry in terms of a parametrized flux rope axis and a parallel transport frame. We derive expressions for the axial and poloidal magnetic field components under the assumption that the total axial magnetic flux is conserved. We find an entire class of possible solutions, which differ by the choice of integration constants, and present the results for a specific example. In general, we find that the twist of the magnetic field locally changes when the geometry deviates from a cylinder or torus. This new approach also allows us to generate completely new types of in situ magnetic field profiles which strongly deviate from those generated by cylindrical or toroidal models.

astro-ph.SR↗