arXiv subjects

Amaia Razquin

Publications and source records attributed to Amaia Razquin.

8 recordsLinked to original sources

arXiv2026

Comprehensive solar eruption analyses enabled by the tools of the SOLER project

Solar eruptions comprise of a multitude of phenomena such as flares, coronal mass ejections (CMEs), large-scale coronal waves, radio bursts, and energetic particles traveling through interplanetary space. These phenomena are observed with a variety of instrumentation, including remote sensing and in-situ detectors. Obtaining a global understanding of a solar eruption often requires the analysis of various of these different datasets, including a multitude of analysis and modeling tools and a wide range of expertise. Usually, such a comprehensive analysis can only be achieved by a skilled and broad team. The Energetic Solar Eruptions: Data and Analysis Tools (SOLER) project aims at creating a comprehensive analysis platform for the study of solar eruptions that allows a single user to easily apply analysis methods addressing various counterparts of the solar event. Therefore, each partner of the project developed Python-based software, including interfaces in the form of Jupyter Notebooks, which provides application examples and concise step-to-step documentation. In this paper we introduce the comprehensive solar-eruption-analysis infrastructure developed within the SOLER project. We explain where to find the software, how to use it, and give dedicated use-case examples of how to employ selected tools in a combined manner.

physics.space-ph↗

arXiv2026

The DIRECD coronal mass ejection direction catalog: three-dimensional propagation inferred from coronal dimmings

Coronal mass ejections (CMEs) are among the primary drivers of space weather disturbances at Earth, yet their early propagation in the low corona remains poorly constrained owing to occultation and projection effects inherent to coronagraph observations. Coronal dimmings offer an alternative diagnostic to infer CME propagation direction directly from the low corona. We present the DIRECD CME Direction Catalog, a unified dataset of three-dimensional CME propagation directions derived via the DIRECD (Dimming Inferred Estimation of CME Direction) method, which reconstructs CME cone geometry from SDO/AIA 211 Å coronal dimming observations. The catalog comprises 64 events spanning 2010-2026, combining 31 Solar Cycle 25 (2021-2026) events with 33 events from prior studies. For each event we report the 3D propagation direction, 2D inclination angles, angular width, and cone height. Statistical analysis reveals a systematic asymmetry in low-coronal CME propagation: meridional inclinations exhibit a systematic tendency toward latitude-dependent deflection, with poleward deflections more pronounced at higher source latitudes, while equatorial inclinations show no significant dependence on source longitude. This is consistent with low-coronal CME trajectories being governed primarily by local active-region magnetic topology, with the large-scale coronal field and heliospheric current sheet assuming a progressively dominant role at greater heliocentric distances. Incorporating DIRECD-derived propagation directions into CME arrival forecasts improves predictions of geomagnetic storm intensity, raising the correlation with observed storm strength from r = 0.58 to r = 0.70 when combined with CME speed. The DIRECD software, catalog, and all associated data products are publicly available to support space weather research.

astro-ph.SR↗

arXiv2026

DEM analysis of the 6 September 2011 large-scale coronal wave

Large-scale coronal waves are globally propagating intensity enhancements in extreme-ultraviolet (EUV) and soft X-ray (SXR) observations, associated with solar flares and coronal mass ejections (CMEs). They are interpreted as low-coronal signatures of a large-amplitude fast magnetosonic wave. On 6 September 2011, a fast (v = 1000 km/s) large-scale coronal wave accompanied an eruptive X2.1 class flare. A segment of the wave front temporarily dissappeared in EUV channels sensitive to quiet-Sun plasma, while it remained visible in higher temperature channels. We apply differential emission measure (DEM) diagnostics to SDO/AIA EUV observations to derive local density, temperature, emission measure, and DEM distributions, and examine their temporal evolution during the wave passage. The wave passage causes increases of 6-8% in density and 10-18% in temperature. While the density increase is comparable to earlier reports, the temperature increase exceeds expectations. This indicates that the temperature enhancement cannot be explained by compressional adiabatic heating alone, and instead suggests the presence of additional heating mechanisms, such as magnetic reconnection or wave mode conversion. During the temporary disappearance of the wave, the plasma parameters at the wave front increase, but with a strong spatial variability, with density increases ranging from 1% to 10%. The initial temperature in the affected area is notably higher than typical quiet-Sun regions (T > 1.7 MK), which allows plasma to be heated beyond the peak response of the AIA 193 and 211 Åchannels. We conclude that the apparent temporary disappearance of the wave front is primarily due to the combined effects in the intensity of the CME-associated coronal dimming following the wave and the wave itself, with heating further reducing its detectability in channels sensitive to quiet-Sun temperatures.

astro-ph.SR↗

arXiv2026

Magnetic flux systems involved in the May 2024 solar energetic events from AR 13664 inferred through coronal dimmings

Coronal dimmings are transient depletions of coronal plasma observed in extreme ultraviolet and soft X-rays, interpreted as low-corona signatures of coronal mass ejections (CMEs). Their evolution is closely linked to CME dynamics, flare reconnection, and large-scale coronal magnetic restructuring. In May 2024, active region (AR) 13664 produced 66 > M-class flares and multiple fast CMEs that caused the strongest geomagnetic storm since 2003. We analysed 16 on-disc dimmings observed in SDO/AIA 211Ådata between May 1-14, 2024. We extracted dimmings using logarithmic base-ratio thresholding, and derived magnetic properties from SDO/HMI line-of-sight magnetograms. We identified flare ribbons in AIA 1600Ådata via adaptive thresholding, and computed reconnection fluxes from radial magnetic field maps. We examined the magnetic flux systems involved in the eruptions using PFSS and NLFF extrapolations. We found correlations between dimming and flare ribbon properties stronger than previously reported. The dimming morphology evolved systematically, with southward expansion before May 9 and northward afterward, coinciding with a shift in flare ribbon locations between two mayor east-west polarity inversion lines (PILs). These changes imply the presence of two distinct magnetic domains. The PFSS extrapolations showed that southward (northward) dimmings are mainly strapping flux dimmings with magnetic field lines vaulting above the southern (northern) PIL. The final extent of the dimmings was then given by the exterior flux involved in the eruption via stretching and reconnection. One event revealed an extended quiet-Sun dimming likely triggered by EUV wave-induced field opening.

astro-ph.SR↗

arXiv2025

Validating DIRECD: Statistical Evaluation of Coronal Mass Ejections Direction Estimates from Coronal Dimmings

Coronal mass ejections (CMEs) are among the most energetic phenomena in our solar system, with significant implications for space weather. Understanding their early dynamics remains challenging due to observational limitations in the low corona. We present a statistical evaluation of the DIRECD (Dimming InfeRred Estimation of CME Direction) method, which provides a novel approach to determining initial CME propagation directions using coronal dimmings. We analyze 33 coronal dimming events well observed by SDO/AIA and validate our DIRECD results with 3D reconstructions from the Graduated Cylindrical Shell (GCS) model. We find generally good agreement between the DIRECD-derived inclinations and the GCS model. In the meridional plane (north--south direction), the mean difference in inclinations is $0.3^\circ \pm 7.8^\circ$. In the equatorial plane (east--west direction), the mean difference is $-2.9^\circ \pm 18.9^\circ$. In 3D, the inclinations show a mean difference of $1.2^\circ \pm 10.4^\circ$. We further visually compare our method by projecting the DIRECD cones onto LASCO/C2 observations, and verify the model's ability to capture both the primary CME structure and associated secondary dimming regions. This work establishes DIRECD as a powerful, observationally grounded technique for determining the initial CME direction, offering new insights that complement existing reconstruction methods. The technique's unique capability to determine early CME direction in the low corona using coronal dimmings observed in EUV images makes it particularly valuable for improving space weather forecasting models.

astro-ph.SR↗

arXiv2025

Coronal dimmings from active region 13664 during the May 2024 solar energetic events

Coronal dimmings are regions of transiently reduced brightness in extreme ultraviolet (EUV) and soft X-ray (SXR) emissions associated with coronal mass ejections (CMEs), providing key insights into CME initiation and early evolution. During May 2024, AR 13664 was among the most flare-productive regions in recent decades, generating 55 M-class and 12 X-class flares along with multiple Earth-directed CMEs. The rapid succession of these CMEs triggered the most intense geomagnetic storm in two decades. We study coronal dimmings from a single active region (AR 13664) and compare them with statistical dimming properties. We investigate how coronal dimming parameters - such as area, brightness, and magnetic flux - relate to key flare and CME properties. We systematically identified all flares above M1.0, all coronal dimmings and all CMEs (from the CDAW SOHO/LASCO catalogue) produced by AR 13664 during 2024 May 1 - 15, and studied the associations between the different phenomena and their characteristic parameters. We detect coronal dimmings in 22 events, with 16 occurring on-disc and six off-limb. Approximately 83% of X-class flares and 23% of M-class flares are associated with CMEs, with 13 out of 16 on-disc dimmings linked to CME activity. Our results support the strong interplay between coronal dimmings and flares, as we find increased correlations between flare and dimming parameters in this single-AR study compared to the general dimming population. Furthermore, we confirm that coronagraphic observations, unable to observe the lower corona, underestimate correlations between CME velocities and dimming parameters, as they fail to capture the early CME acceleration phase. This highlights the critical role of dimming observations in providing a more comprehensive understanding of CME dynamics.

astro-ph.SR↗

arXiv2024

Estimating early coronal mass ejection propagation direction with DIRECD during the severe May 8 and follow-up June 8, 2024 events

On May 8, 2024, solar active region 13664 produced an X-class flare, several M-class flares, and multiple Earth-directed Coronal Mass Ejections (CMEs). The initial CME caused coronal dimmings, characterized by localized reductions in extreme-ultraviolet (EUV) emissions, indicating mass loss and expansion during the eruption. After one solar rotation, on June 8, 2024, the same region produced another M-class flare followed by coronal dimmings observed by the SDO and STEREO spacecraft. We analyzed early CME evolution and direction from coronal dimming expansion at the end of the impulsive phase using the DIRECD (Dimming Inferred Estimation of CME Direction) method. To validate the 3D CME cone, we compared CME properties from the low corona with white-light coronagraph data. The May 8 CME expanded radially, with a 7.7 deg inclination, 70 deg angular width, and 0.81 Rsun cone height, while the June 8 CME had a 15.7 deg inclination, 81 deg width, and 0.89 Rsun height. Our study shows that tracking low coronal signatures, like coronal dimming expansion, can estimate CME direction early, providing crucial lead time for space weather forecasts.

astro-ph.SR↗

arXiv2023

Track reconstruction for the COMET Phase-II experiment with ACTS

An implementation of A Common Tracking Software (ACTS) toolkit for signal electron reconstruction for the COMET muon to electron conversion experiment is discussed. The COMET experiment in J-PARC, Japan, will search for neutrinoless conversion of muons into electrons in the field of an aluminium nucleus, a lepton flavour violating process, aiming target sensitivity of $10^{-17}$. To achieve its scientific goals, the experiment requires a reconstructed momentum resolution of lower than 150 keV/c. For the first time by applying ACTS to signal events in the 100 MeV energy range with multiple-turn trajectories in the presence of background events, it is found that the reconstruction efficiency is around 14\% with no fake reconstructed events. The implementation details, performance, and issues of ACTS in the context of COMET are presented.

hep-ex↗