2024 Boulder Solar Day Abstracts

First Name	Last Name	University or Institution	Authors	Affiliations / Institutes	Title	Abstract
Presentations
David	Afonso Delgado	High Altitud Observatory (HAO)	David Afonso Delgado(1), Rebecca Centeno Elliot (2), Roberto Casini(3)	High Altitud Observatory(1), High Altitud Observatory(2), High Altitud Observatory(3)	"Ultraviolet Spectropolarimetry: Mapping Magnetic Field Stratification in Solar Eruptions	The study of ultraviolet line polarization signals is one of the primary windows to study the magnetism of the upper layers of the chromosphere. The unprecedented results from the two Chromospheric LAyer Spectropolarimeter missions (CLASP2 and CLASP2.1) have demonstrated the suitability of the spectral region around the Mg II h & k resonant doublet to infer the magnetic field configuration in the solar chromosphere. Furthermore, several studies have advocated for the inclusion of the Fe II lines within the 250-270 nm spectral range as an optimal complement to the Mg II h and k spectral window lines for a comprehensive examination of the solar magnetic fields. Currently, the Chromospheric Magnetism Explorer (CMEx) mission is being developed with the purpose of exploiting the full potential of this ultraviolet region of the solar spectrum to quantify the magnetic field vector throughout the solar atmosphere. Magneto-hydrodynamic (MHD) simulations predict that certain types of solar eruptions require the prior formation of a magnetic flux rope (MFR). The MFR develops from a simpler sheared magnetic arcade (SMA) some time before the eruption occurs. The stratification of the magnetic field from the photosphere to the chromosphere is very different between these two plasma structures. In this work, we performed complex radiative transfer calculations in MHD simulations representative of both scenarios to model synthetic observations of the Mg II and Fe II polarization profiles in the 255 - 281 nm spectral window. Analyzing these synthetic observations, we demonstrate that a space mission like CMEx can infer the stratification of the magnetic field in active regions of the solar atmosphere. This approach will allow us to determine the precise process by which an SMA evolves into an MFR, confirming the validity of existing models of solar eruption formation.
Thomas	Ayres	University of Colorado (CASA)	Thomas Ayres	CU/CASA	In the Trenches of the Solar-Stellar Connection: X-ray Variability and Cycles of Cool Stars	A defining, yet still mysterious, aspect of solar activity is its ebb and flow over decadal timescales.  The 11-yr sunspot cycle is a hundred times longer than either the convective turnover time or the solar rotation period.  These are the two ingredients in the so-called Rossby number, which is thought to control the internal "dynamo,'' the elusive engine responsible for large-scale surface magnetic activity.  The solar cycle is especially prominent in coronal (1–2 MK) soft X-rays with an amplitude of 4–100, depending on energy band; whereas famous chromospheric (10,000 K) Ca II HK varies only tens of percents.   The high-contrast X-ray modulation has a major impact on Space Weather in our heliosphere; as do stellar counterparts for habitability of their exoplanets. Little is known about stellar X-ray variability and cycles, however, because long-term monitoring efforts– equivalent to the heroic multi-decade Mt. Wilson Ca II program, which captured hundreds of late-type stars– have been rare. The present study trolled the archives of the "Big Three" contemporary X-ray observatories: Chandra, XMM-Newton, and Swift, all operating for two decades or more. About twenty late-type stars have been well-enough observed to assess long-term X-ray variability, especially the nearby Alpha Centauri triple system: A (G2V), B (K1V), and C (Proxima: M5V). Curiously, large-amplitude cycles are commonly found in lower activity Sunlike stars, whereas hyper-active objects, like rapidly spinning "cannibal" K dwarf AB Doradus and short-period RS CVn binary AR Lacertae, show flat long-term X-ray trends, but punctuated by frequent, intense flares. Oddly, some stars display ultra-short X-ray cycles of only 1–2 yr, whereas others are longer than the Sun's, for example nearly 20 yr for Alpha Cen A. The diversity of X-ray cycles among outwardly similar stars cautions that the dynamo has a more complex dependence on stellar properties than heretofore suspected.
Benjamin	Berkey	HAO/MLSO	Benjamin Berkey	HAO/MLSO	Flying to work: Partial MLSO recovery from the 2022 lava flow to support the 2024 solar eclipse	Just after Thanksgiving 2022, the Mauna Loa volcano erupted, sending lava flows within 2 miles of the MLSO observatory and cutting off road access and power. In the summer of 2023, UCAR committed to restoring power to MLSO by helicopter in time for the 2024 eclipse. With significant efforts from the UCAR teams, we were able to temporarily repower the observatory and test all of the subsystems to prepare for eclipse observations. The road recovery and repowering continue, with normal operations expected in Spring 2025. This presentation will discuss the recovery process, eclipse operations, and our plan to move forward. You can download our eclipse and related data from: https://mlso.hao.ucar.edu/mlso_data_calendar.php
Subhamoy	Chatterjee	Southwest Research Institute	Subhamoy Chatterjee(1), Andrés Muñoz-Jaramillo(1), Anna Malanushenko(2)	(1) SwRI, Boulder, CO, USA, (2) High Altitude Observatory, NCAR, Boulder, CO, USA.	Deep Generative model that uses physical quantities to generate and retrieve solar magnetic active regions	Deep generative models have shown immense potential in generating unseen data that has properties of real data. These models learn complex data-generating distributions starting from a smaller set of latent dimensions.  However, generative models have encountered great skepticism in scientific domains due to the disconnection between generative latent vectors and scientifically relevant quantities. In this study, we integrate three types of machine learning models to generate high-quality solar magnetic patches in a physically interpretable manner and use those as a query to find matching patches in real observations. We find that the retrieved real data shares the same physical properties as the generated query.   This elevates Generative AI from a means-to-produce artificial data to a novel tool for scientific data interrogation.
Steven	Cranmer	University of Colorado Boulder	Steven R. Cranmer (1)	(1) University of Colorado Boulder	Parker Solar Probe: Six Years of Discovery that Revolutionized our Understanding of the Sun	Launched just over six years ago, NASA's Parker Solar Probe (PSP) has ventured closer to the Sun than any other spacecraft and has broken the speed record for the fastest human-made object. PSP's primary science objectives have been to: (1) trace the flow of energy that heats and accelerates the solar corona and solar wind, (2) determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind, and (3) explore the mechanisms that accelerate and transport energetic particles. This presentation is an update of one that I gave at Boulder Solar Day in 2018, just prior to PSP's launch. I'll review some of the unprecedented data collected by PSP, such as the first samples of solar wind inside the Alfven surface, multiple encounters with magnetic "switchbacks" that may probe small-scale coronal structure, and a plethora of kinetic plasma measurements that have filled in a huge gap between prior in-situ data and remote-sensing photon data. I also hope to outline how the work is only now beginning on using these unique measurements as constraints on theoretical models; specifically in determining the relative contributions of waves, turbulence, instabilities, and magnetic reconnection events that are responsible for producing the fast and slow solar wind. We are only a few months away from PSP's final Venus flyby and the first perihelion at its closest heliocentric distance of only 9.8 solar radii, so it is likely there will be even more surprises to come.
João	da Silva Santos	National Solar Observatory (NSO)	João da Silva Santos(1), Momchil Molnar(2), Ivan Milic(3), Matthias Rempel(2), Kevin Reardon(1), Jaime de la Cruz Rodriguez(4)	(1) National Solar Observatory, Boulder, United States; (2) High Altitude Observatory, Boulder, United States; (3) Institute for Solar Physics (KIS), Freiburg, Germany; (4) Stockholm University, Stockholm, Sweden	Evaluating acoustic wave flux contributions to spatially resolved chromospheric radiative losses	Accurately assessing the balance between acoustic wave energy fluxes and radiative losses is important for understanding the thermal regulation of the solar chromosphere. We examine this energy balance using non-local thermodynamic equilibrium (NLTE) inversions, comparing deposited acoustic flux and radiative losses under various solar conditions. Spectroscopic data from the Interferometric BIdimensional Spectrometer (IBIS) and the Interface Region Imaging Spectrograph (IRIS) are used to derive spatially resolved velocity power spectra and cooling rates across different heights in both quiet and active conditions. Our findings suggest that NLTE inversions may underestimate acoustic fluxes at all chromospheric heights and overestimate radiative losses, particularly when the availability of spectral diagnostics is more limited. However, even after accounting for these biases, the ratio of acoustic flux to radiative losses remains below unity in most regions observed, especially in the higher layers of the chromosphere. This work highlights the reliability of NLTE inversions in determining atmospheric parameters and wave fluxes, emphasizing the need for refining inversion techniques and expanding the analysis to include magnetic field impacts on wave propagation and dissipation.
Ryan	French	National Solar Observatory	Ryan French	National Solar Observatory	Celestial Shadows & Dancing Lights: How Sun science can capture public interest	Total solar eclipses and extreme aurora events are among the most dramatic natural events available to us on Earth, captivating humanity long before written history. Earlier this year, many of us experienced both events within a relatively short time window, during the April 8th total solar eclipse and May 12th G5 geomagnetic storm. In this talk, we will explore historic and recent reactions of society to eclipses and aurora, and discuss how public awareness of these events can be redirected to a wider interest in solar physics.
Alison	Jarvis	CIRES/NOAA-NCEI	Alison Jarvis (1,2), Christian Bethge (1,2), Jonathan M. Darnel (1,2), J. Marcus Hughes (3), Fadil Inceoglu (1,2), Donald Schmit (1,2)	(1) Cooperative Institute for Research in Environmental Sciences, (2) NOAA National Centers for Environmental Information, (3) Southwest Research Institute	Methodology and Validation of NOAA's Thematic Map Algorithm for Automated Solar Feature Identification	Real-time, automated detection and classification of solar features such as active regions, coronal holes and flares is a valuable tool in monitoring and predicting space weather events. Various algorithms have been developed for this purpose, one example of which is the NOAA operational, machine-learning based algorithm which generates a product called Thematic Maps. This near real-time algorithm takes an input of Solar Ultraviolet Imager (SUVI) composite images in six extreme ultraviolet wavelengths, and classifies each pixel into categories representing different solar features, yielding a “map” which comprehensively describes current activity on the sun. Here we discuss the methodology behind the operational algorithm, including how the random forest framework was leveraged to optimize the results. We also demonstrate our process and challenges in validating the Thematic Map, and explore the quantified performance in comparison to both hand-drawn expert labels and long-term archives of algorithm-derived labels. Finally, we review potential improvements to the Thematic Map, including incorporating additional sources of input data, and implementing more sophisticated types of machine learning.
Larisza	Krista	University of Colorado	Larisza Krista	University of Colorado/CIRES, NOAA/NCEI	Flare forecasting: how about EUV?	Solar flares produce radiation across the whole electromagnetic spectrum. Nevertheless, their classification, monitoring, and now-casting is largely based on X-ray emission. In this study, we focus on short-lived, bright EUV events in the flaring region that occur minutes to hours before the eruptions. Our goal is to decipher how these events are related to flares and identify precursors to solar eruptions. The Detection and EUV Flare Tracking (DEFT; Krista and Chih, 2021) tool was developed to automatically identify flare precursors in EUV observations in a fast and consistent manner, with minimal computational overhead. DEFT currently uses GOES/SUVI 304 A observations to detect, group and flag sudden impulses that could be precursors to flares. In this study we analyzed signatures before 351 flares (150 C, 150 M and 51 X class flares) that occurred between 2017-2024. Across these magnitudes, precursors were detected for 93% of the flares when using a 6-hour window before the flare start times. Using superposed epoch analysis, we found that elevated precursor activity tends to occur across all magnitude flares in the last two hours before the flares. The frequency of precursors gradually increases before M class flares but decreases for C class flares. In the last 20 minutes there is a significantly higher precursor frequency, pixel count and power associated with M class flares than C class flares.  We suggest that the observed EUV precursors are signatures of small-scale magnetic reconnection events, and the increasing frequency of precursors could indicate increasing instability and impending flare initiation. Continuing research on EUV precursors is essential to better understand pre-flare processes that influence magnetic instability prior to flares. The consistent and reliable detection and differentiation of EUV precursors could also complement and significantly improve current flare forecasting efforts.
Bhishek	Manek	LASP, CU Boulder	Bhishek Manek (1), Nicholas Brummell (2), Yang Liu (3), Rudi Komm (4)	LASP, UCSC, Stanford University, NSO	Twist in Origin of Solar Magnetic Helicity	Magnetic fields on the Sun play an essential role in the solar interior dynamics and solar surface activity. These fields are readily observed as active regions (ARs) and bipolar sunspots on the solar surface, and their formation and cyclic emergence from the interior is a subject of great interest studied under the umbrella of solar dynamo theory.  Recent observational laws regarding magnetic fields have focused on the helicity of ARs. Solar kinetic, magnetic or current helicity is a quantitative measure of the topological complexity of the respective fields, and play a vital role in our understanding of the solar magnetic fields and plasma dynamics. They provide constraints on the workings of the solar dynamo, are expected to provide the underlying energy source for extreme space weather events. Observational proxies of magnetic and current helicity reveal a trend known as the "Solar Hemispheric Helicity Rules" (SHHR): solar magnetic fields in the Northern Hemisphere tend to have negative sign of helicity, and fields in the Southern Hemisphere tend to have positive sign of helicity. The rule exhibits a considerable amount of violations and temporal variability. The study of origin of this ordered helicity is of significant importance. Traditionally studies focused on this question have appealed to the impact of rotating turbulent convection on rising magnetic flux from the solar interior in imparting the SHHR-like helicity signatures. Recent advances with alternate mechanisms have worked on the premise that flux tubes rising from the solar interior are not isolated but rise through a field-filled environment, leading to purely magnetic effects that work to filter out specific helicity signed structures, commensurate with SHHR. We present 3D Cartesian simulation results that model the rise of twisted flux tubes through a background field, and show that the resultant dynamics lead to the observed helicity signatures under SHHR.
Travis	Metcalfe	Center for Solar-Stellar Connections	Travis Metcalfe	Center for Solar-Stellar Connections, WDRC	Weakened Magnetic Braking: what it tells us about stellar dynamos	In 2016, the Weakened Magnetic Braking (WMB) hypothesis was proposed to explain anomalously rapid rotation in old field stars observed by the Kepler mission. Since then, indirect evidence of this phenomenon has accumulated in the form of reliable rotation periods and ages for much larger samples of stars. In the past few years, direct evidence has started to emerge from spectropolarimetric inferences of magnetic field strength and morphology for a sample of field stars that span the transition to WMB. These measurements demonstrate unambiguously that sun-like stars enter the WMB regime at a Rossby number slightly below the solar value, suggesting that our own solar system is already in this regime. Time series observations and numerical simulations of the Sun and other cool stars provide important constraints on the underlying transition in stellar dynamos that ultimately leads to WMB, through the disruption of magnetic organization on the largest spatial scales. I will provide an overview of the direct evidence of WMB from recent estimates of the wind braking torque for sun-like stars, and I will summarize what these constraints tell us about the evolution of stellar dynamos beyond the middle of main-sequence lifetimes.
Mark	Miesch	CIRES/Univ. Colorado			Solar Cycle Prediction at NOAA's Space Weather Prediction Center	Solar cycle prediction is arguably the oldest and most enduring example of space weather forecasting. There are at least two reasons for making a prediction of how the current and future solar cycles will proceed. The first concerns the nature of scientific discovery; theories and models of the solar dynamo must demonstrate predictive skill in order to set themselves apart from competing theories and models. The main goal of this research perspective is physical insight into the nature of the dynamo. But, there is also the operational perspective where the main goal is to provide actionable information to space weather stakeholders. Here predictions must not only be accurate but also robust and transparent. Reliable uncertainty quantification and assimilation of all available data is essential. In this talk I will focus on how NOAA's Space Weather Prediction Center (SWPC) currently addresses solar cycle prediction from an operational perspective. This includes a series of solar cycle prediction panels and a new product, introduced in 2023, to continually update the 2019 panel prediction as new data becomes available. The new product is now available on SWPC's new Space Weather Prediction Testbed (SWPT) website. It is based on nonlinear curve fits to the international sunspot number and F10.7 radio flux, with uncertainties quantified by applying the same method to previous cycles at the same time in each cycle. A preliminary operational forecast for Cycle 26 will also be presented.
Andrés	Muñoz-Jaramillo	Southwest Research Institute	Andrés Muñoz-Jaramillo(1), Benoit Tremblay(2), Gautier Bardi de Fourtou(3), Rituparna Curt(4), Brianna Isola(5), Marcella Scoczynski(6), Christoph Schirninger(7), Robert Jarolim(2), Cooper Downs(8),  Ronald Caplan(8)	(1) Southwest Research Institute, (2) High Altitude Observatory, (3) Mines Paris - PSL university, (4) Stanford University, (5) University of New Hampshire, (6) Federal University of Technology - Parana, (7) University of Graz, (8) Predictive Science	SuNeRFs: From Multi-Viewpoint Satellite Images of the Sun to a 4D model of the Corona's Electron Density & Plasma Temperature	Multi-thermal Extreme Ultraviolet (EUV) images provide valuable insight on the different regions of the solar atmosphere. However, instrument inhomogeneity and limited number of viewpoints makes studying the 3D of the Sun difficult. We propose to leverage multi-viewpoint EUV observations and a deep learning methodology to generate a 4D (3D + temporal) representation of the solar atmosphere, providing insight on long-standing problems in solar and stellar physics from a new perspective. We develop an updated version of the Sun Neural Radiance Fields (SuNeRFs) that now leverages time sequences of multi-thermal EUV and X-ray images captured from multiple viewpoints to generate a 4D data-driven reconstruction of the electron density and plasma temperature in the corona. The SuNeRFs model includes radiative transfer and accounts for instrument temperature responses. As such, it more accurately captures the thermal structure of the solar atmosphere, and can incorporate EUV images from available sources (SDO/AIA, STEREO/EUVI, SolO/EUI, GOES/SUVI, Hinode/XRT) without inter-calibration. An analytical stellar model as well as a time-dependent MHD simulation from Predictive Science Inc. are used for validation. We also use these ground truths to test the SuNeRFs' ability to work with various viewpoints, inhomogenous sets of EUV observations, etc. SuNeRFs act as virtual observatories that can be placed at any point in the solar system to render novel views of the Sun, including non-ecliptic views, its poles, etc. When combined with the MEGS-AI tool which translates EUV images into irradiance, we can estimate the spectral irradiance of the 3D Sun at any point in the solar system and thus measure the impact of the Sun on planets such as Mars.  This work is the research product of FDL-X Heliolab a public/private partnership between NASA, Trillium Technologies Inc (trillium.tech) and commercial AI partners.
Alin	Paraschiv	National Solar Observatory	Alin Paraschiv	National Solar Observatory	A Novel Method for Inferring Solar Coronal 3D Magnetic Fields using IQU-only Spectropolarimetry	With the commissioning of new generation instrumentation and the recent advances in understanding the theoretical aspects of solar coronal polarization, new science interpretation and inversion of polarized infrared observations from the ground is highly required at this time. Currently, it is still challenging to measure full Stokes polarization of forbidden lines formed in the solar corona. We showcase a novel inversion method that separates the problem of inferring coronal vector magnetic fields into two parts: i. Utilizing Stokes IQU observations to disentangling the magnetic field orientation; ii. Estimate the magnetic field strength via magnetically-induced Doppler plasma oscillations. Thus, a realization of the vector magnetic field configuration can be inferred without the formal need of including Stokes V circular polarization observations, under a distinct set of assumptions.  We will present this "IQUD" method and describe the upgrades to the open-source CLEDB code package that can be used for inferring the geometrical, thermal and vector magnetic information of the Sun's corona. This approach can be currently applied to intensity and linear polarization data, of at least two coronal lines, like the Fe XIII 1074.68 nm and 1079.79 nm infrared pair, observed by the MLSO COMP/uCoMP, DKIST Cryo-NIRSP, and DKIST DL-NIRSP instruments.
Benoit	Tremblay	High Altitude Observatory	Benoit Tremblay(1), Andrés Muñoz-Jaramillo(2), Robert Jarolim(3),    Anna Jungbluth(4), Kyriaki-Margarita Bintsi(5), Christoph Schirninger(6), Gautier Bardi de Fourou(7), Rituparna Curt(8), Marcella Scoczynski(9), Briani Isola(10)	High Altitude Observatory (1), SwRI (2), High Altitude Observatory (3), ESA (4), Imperial College London (5), University of Graz (6), NASA JPL (7), Stanford university (8), University of New Hampshire (10))	AI to Enhance the Capabilities of EUV-observing Satellites and Estimate Spectral Irradiance	Multiple satellites capture images of the Sun in Extreme Ultraviolet (EUV) light. However, only the Solar Dynamics Observatory (SDO) was equipped with instruments that measure the Sun's EUV spectral irradiance (i.e., MEGS-A and MEGS-B onboard the Extreme Ultraviolet Variability Experiment (EVE) suite). The MEGS-A instrument malfunctioned in 2014, making it impossible to measure the full irradiance spectrum ever since.  Using AI, we explore the translation of a set of EUV images of the Sun into spectral irradiance, effectively replacing the malfunctioning MEGS-A instrument onboard SDO, and in some cases providing the full spectrum of irradiances. In other words, we generate a virtual irradiance instrument, MEGS-AI, for SDO. Using an Image-to-Image translation tool (ITI), this virtual instrument can also be trained and added on other EUV-observing satellites like STEREO, GOES, SolO, and the upcoming VIGIL satellite, enabling unprecedented irradiance estimates from additional satellite missions. In the case of the STEREO twin-satellites and VIGIL, this enables estimates of spectral irradiance prior to the Sun rotating into Earth's view, which directly enables the forecast of enhanced irradiance. We provide such an example using STEREO-B. Additionally, we explore different combinations of images in different EUV channels and evaluate their contributions in estimating different irradiance channels. Finally, when combined with a neural radiance field model of the Sun (SuNeRFs), MEGS-AI can estimate spectral irradiance from any viewpoint in the solar system, enabling for the first time a complete 4pi spectral irradiance map of the Sun. This can be directly used to estimate the Sun's impact on other planets in the solar system and to determine the total solar irradiance output in multiple EUV spectral bands.
Posters
Julie	Barnum	LASP	Julie Barnum (1) Shawn Polson (1)	LASP	The Python in Heliophysics Community: an overview	Many Heliophysics, Space Weather, and Space Physics software projects are being developed in, or converted to, the Python programming language. The Python in Heliophysics Community (PyHC) has worked over the past six years to bring together the solar and space physics communities for the purpose of coordinating Python software development efforts. The goal of this work is to share knowledge and lessons learned, reduce the incidence of duplicated efforts, ascertain potential collaborations between PyHC projects, and ensure that existing software tools are interoperable and widely available. This submission will showcase the efforts of the PyHC and increase awareness of the resources that the PyHC provides.
Sarah	Bruce	University of Colorado Boulder	Sarah Bruce(1), Kevin Reardon(1)(2)	(1) University of Colorado Boulder, (2) National Solar Observatory	K-Coronal Temperatures Eclipse Experiment	During the total solar eclipses of 20 April, 2023 in Exmouth, Australia and 8 April, 2024 in Texas, we carried out several experiments aiming at investigating the low solar corona. We used a low dispersion (0.28 Ã/pixel) slit spectrograph to obtain spectra covering the interval from 3600-4700 Ã between 1-1.5 solar radii. The scattering of the photospheric emission by the high-temperature, high-velocity coronal electrons smears out any Fraunhoffer lines, but leaves broad spectral signatures that can be used to infer the magnitude of the broadening and hence the coronal electron temperature (Cram, 1976). Such measurements have been carried out a few times in the past (e.g. Ichimoto, et al., 1996; Reginald, 2009) and are the basis of the upcoming CODEX mission. We will describe our experimental setup and present our analysis of these spectra, which also show several emission lines in this wavelength interval. We further obtained slit jaw images of the K-corona above an active region, which show small scale structures which we compare with images from SDO/AIA and GONG/H-alpha. Additionally, using the FORWARD software package from HAO, we modeled the white-light corona at the time of the eclipses. Using the FOWARD framework we wrote code to simulate an intensity spectrum integrated along the line of sight for each point in the corona, which we compare to data observed in the eclipses.
Joan	Burkepile	NCAR/High Altitude Observatory	J.T. Burkepile (1), G. de Toma (1), M. D. Galloy (1), B. Berkey (1), S. Tomczyk (1), D. Gary (3), B. Chen (4), A. Pevstov (5), D. Kolinski (1), L.Perez-Gonzalez (1), M. Cotter (1)	(1) NCAR High Altitude Observatory, (2) Solar Scientific LLC, (3) New Jersey Institute of Technology (NJIT), (4) National Solar Observatory (NSO)	Synergies of ground-based solar observations with space-based observations of the corona and solar wind	Ground-based observations in the visible, near IR and radio provide critical information on plasma and magnetic field conditions and sites of magnetic reconnection and particle acceleration in the low and middle corona, where CMEs originate. Ground-based magnetic field measurements of the photosphere and chromosphere, coupled with helioseismology observations of far-side active regions, provide improved magnetic boundary conditions for models of the coronal magnetic field and solar wind. We highlight how these data connect properties of ambient structures in the low and middle corona with the space-based observations of the corona and solar wind. Ground-based data also provide crucial information on the formation and early dynamics of CMEs and related solar activity.
Giuliana	de Toma	NCAR/HAO	Giuliana de Toma, Joan Burkepile, and Steven Tomczyk	NCAR/HAO	Observations of the inner and middle corona with the MLSO coronagraphs	The two coronagraphs at the Mauna Loa Solar Observatory (MLSO) take daily, weather permitting, synoptic observations of the solar corona in a height range not commonly observed by other ground-based and space-based instruments. The K-Coronagraph (K-Cor) measures polarization brightness in the visible (720-750nm) from ~1.05 to 3 solar radii with 15s cadence and a spatial resolution of ~5.5 arcsec/pixels. The Upgraded Coronal Multi-channel Polarimeter (UCoMP) provides intensity, line-of-sight velocity, line width, and linear polarization in several visible and IR lines (530-1083nm) from ~1.03 to 2 solar radii with 30-150s cadence and ~3.0 arcsec/pixels spatial resolution. The field-of-views of KCor and UCoMP cover the heights where CMEs accelerate and fill a "gap" in coronal observations from space. The unique MLSO measurements provide information on the morphology, density, magnetic structure, and dynamics of coronal features that extend into the middle corona and can be used to connect structures observed with EUV imagers and space-based white-light coronagraphs. We provide examples of quiescent coronal structures, e.g. pseudo-streamers and coronal cavities, as well as eruptive events observed with the two MLSO coronagraphs.
Michael	Galloy	MLSO/HAO/NCAR	Michael Galloy(1), Steven Tomczyk(1)(2), Enrico Landi(^3), Ben Berkey(1), Joan Burkepile(1), Marc Cotter(1), Dennis Gallagher(1)(4), Rob Graves(1), Philip Oakley(4), Lisa Perez-Gonzalez(1), Scott Sewell(1), Giuliana de Toma(1), Zihao Yang(5), P Zmarzly(1)	(1) NCAR/High Altitude Observatory, (2) Solar Scientific LLC, (3) University of Michigan, (4) Ball Aerospace, (5) Peking University	UCoMP Calibrated Data in Support of April 2024 Eclipse	NCAR/HAO has released calibrated data from the new Upgraded Coronal Multi-channel Polarimeter (UCoMP; Landi, Habbal and Tomczyk, 2016). The UCoMP is a 20-cm aperture Lyot coronagraph with a Stokes polarimeter and a narrow-band electro-optically tuned birefringent filter that images the intensity, full Stokes polarization, and Doppler shift across coronal emission lines in the visible and near-IR. It has a broader range (530--1083 nm) than CoMP (1074–083 nm), observing 9 emission lines (vs 3 for CoMP). It has a dramatically faster collection of the full Stokes polarization than CoMP, providing higher quality polarimetry and Doppler measurements. UCoMP also has a larger field-of-view (+/- 2 R_Sun) [CoMP ± 1.3 R_Sun], and 6 arcsec spatial resolution (CoMP 9 arcsec). UCoMP provides powerful diagnostic measurements of the coronal magnetic field and plasma properties. The expanded capabilities of UCoMP provide observations over a wide range of coronal temperatures. The larger field-of-view allows it to explore the magnetic and thermal properties of dynamic structures, such as Coronal Mass Ejection (CMEs), and ambient coronal structures, such as coronal cavities, pseudo-streamers, and the polar corona out to greater heights. We provide sample data from UCoMP in support of the April 2024 eclipse in a variety of UCoMP data products.
Amr	Hamada	National Solar Observatory	Amr Hamada (1), Kiran Jain (1), Mitchell Creelman (1), Charles Lindsey (2)	(1) National solar Observatory, (2) North West Research Associates	Far-side Active Regions Based on Helioseismic and EUV Measurements: A New Dataset for Heliospheric Machine Learning Advancements	Active Regions (ARs) are regions of strong magnetic flux in the solar atmosphere. Understanding the global evolution of ARs is critical for solar magnetism as well as for accurate space weather forecasting. We present the first far-side AR dataset based on EUV observation and helioseismic measurements. For the EUV observations, we use synchronic maps at 304 Ã comprised of observations from SDO/AIA and STEREO/EUVI, in heliocentric orbit with direct vantages into the Sun's far hemisphere. We used the brightening of the solar transition region in EUV/304 Ã maps as a proxy for the magnetic regions. For the far-side helioseismic measurements, we used seismic phase-shift maps of the Sun's far hemisphere, computed from helioseismic Dopplergrams observed by NSO/GONG. In this study, we present the first global EUV AR dataset of the whole Sun, providing several basic parameters, such as location, area, tilt angle, EUV brightness, and latitudinal/longitudinal extents of the identified ARs. We also present a similar dataset for the far-side GONG ARs where the helioseismic phase shift parameters are included. Helioseismic far-side GONG ARs are examined, and their success at predicting strong ARs is assessed. We discuss the temporal and spatial evolution for the EUV AR signatures and far-side GONG AR signatures during the ascending and maximum phases of Solar Cycle 24 (2010 May–2016 May). We examine the correlation between the helioseismic signatures and the respective EUV source distributions in the Sun's far hemisphere. We present the first far-side AR butterfly diagram based on helioseismic measurements.
Greg	Kopp	CU / LASP	Greg Kopp	CU / LASP	What the Solar Irradiance Tells Us about the Solar Core	The most accurate and precise SI-traceable solar measurements we have are of the total solar irradiance, which is known to better than four decimal places on an absolute scale. From this, several other solar parameters are derived, such as the IAU-accepted effective solar-surface temperature and even the necessary energy production in the solar core.
Hunter	Leise	Laboratory for Atmospheric and Space Physics	Hunter Leise, Doug Lindholm, Chris Lindholm, Ransom Christofferson, Odele Coddington, Courtney Peck, Don Woodraska, and the LASP Web Team	Laboratory for Atmospheric and Space Physics	LASP Interactive Solar IRradiance Datacenter (LISIRD)	Access to high-quality and readily usable data remains a pivotal challenge within heliophysics. The LASP Interactive Solar IRradiance Datacenter (LISIRD), https://lasp.colorado.edu/lisird/, seeks to address this critical need. LISIRD is a website where researchers can discover, visualize, and download solar data from various missions, instruments, models, and laboratories. LISIRD embraces a collaborative and inclusive approach to data sharing and analysis, empowering researchers of all backgrounds and levels of expertise to engage in heliophysics research. Key features of LISIRD include: - Detailed Metadata: LISIRD provides researchers with comprehensive metadata, offering a wealth of contextual information that enriches the transparency, understanding, and utilization of each dataset. - Interactive Plotting Capabilities: LISIRD offers an array of intuitive and robust plotting tools, enabling researchers to visualize and explore solar datasets effortlessly. - Collaborative Analysis: LISIRD facilitates the convenient saving and sharing of plot configurations, streamlining collaborative research efforts. - Customizable Data Downloads: LISIRD empowers users to download data in various file formats, refine data acquisition by specifying temporal and spectral ranges of interest, and even apply minor operations like variable renaming and time format customization. This flexibility ensures that researchers receive data optimized for their specific workflow requirements. This poster presentation will illustrate the key features of LISIRD, provide details on the datasets it serves, explore opportunities for future improvements and community collaboration, and highlight its invaluable role as a resource for advancing heliophysics research.
Madison	Liebel	Johns Hopkins Applied Physics Laboratory	Madison Liebel (1), Patrick Peplowski (2), David Lawrence (3)	Johns Hopkins Applied Physics Laboratory, Laboratory for Atmospheric and Space Physics	Exploring Solar Events in the Inner Heliosphere using the Psyche Gamma Ray and Neutron Spectrometer	Solar Energetic Particle Events (SEPs), triggered by solar eruptions such as flares or coronal mass ejections, are critical components of space weather dynamics. Understanding the propagation of the Solar Proton Events (SPEs) beyond the Earth's magnetosphere is essential for comprehending solar activity throughout the inner solar system. This project aims to model solar proton flux by utilizing data from the Psyche-16 Neutron Spectrometer, an instrument originally designed to analyze the elemental composition of the metal-rich Psyche-16 asteroid. Leveraging this instrument presents a unique opportunity to monitor SEP events beyond Earth's orbit, providing valuable insights into their behavior in interplanetary space. The project integrates theoretical frameworks, sophisticated computational models, and empirical data from spacecraft missions such as the Geostationary Operational Environmental Satellites (GOES). These elements are combined to analyze the dynamics of SEP propagation, offering a comprehensive approach to studying these energetic particles. By bridging the gap in monitoring SEP flux beyond Earth's magnetosphere, this research enhances our understanding of space weather phenomena and their potential interactions with spacecraft. Furthermore, the study contributes to the broader field of heliophysics by providing a deeper understanding of how SPEs influence the space environment. The integration of data from multiple sources allows for a more detailed and accurate depiction of SEP behavior, which is crucial for predicting and mitigating the adverse effects of space weather.
Bhishek	Manek	LASP, CU Boulder	Bhishek Manek (1), Ben Brown (2), Lydia Korre (3)	LASP & CU Boulder	A self-consistent Convection-Radiative zone achieved from Convection driven at the Solar surface	Solar convection plays an important role in transporting energy, chemical elements, and magnetic fields, in maintaining differential rotation, and in the overall operation of the solar dynamo. Helioseismic techniques like ring-diagram and time-distance used to infer the subsurface structure and amplitudes of deep convection give conflicting results leading to the so-called convective conundrum. Hence, understanding the onset and driving mechanisms of deep solar convection is of crucial importance. In this work, we present 2D and 3D Cartesian simulations that explore the onset and setup of a deep solar convection zone self-consistently atop a radiative interior. We treat the radiative transfer using a Kramers-like opacity, along with a highly unstable near-surface layer, allowing for a self-consistent coupling between the solar convection zone and the radiative interior. We investigate the depth of the formed convection zone, the extent of overshooting convective motions, and the convective spectrum at various depths for a range of non-dimensional parameters. The findings of this study help us better understand the driving processes behind solar convection at the multitude of spatial and temporal scales in which it manifests itself.
Momchil	Molnar	HAO	Momchil Molnar (1), Robert Jarolim(1), Benoit Tremblay (1), Rebecca Centeno (1), Matthias Rempel (1)	NCAR/HAO	Milne-Eddington magnetic field inversions with Physics-Informed Neural Networks	Spectral inversions of solar observations are fundamental for the estimation of the magnetic field in the solar atmosphere. However, spectropolarimetric inversion methods are limited in their sophistication by the high computational demand associated with spatial and temporal regularization, implementing complex physics, etc. In this study we present a novel approach for spectropolarimetric inversions, where we use Physics Informed Neural Networks to solve a Milne-Eddington solar atmosphere to estimate the magnetic field. We train our model to determine a smooth parameter space to fit the observed spectral line profiles, applying implicit spatial (and temporal) regularization with no additional memory requirement. We further extend our method to account for the instrumental PSF, enabling an informed spatial coupling. Finally, we apply our method to observations from Hinode/SOTSP. Our method can operate with minimal memory requirements on modern GPUs, while making an efficient use of the spatio-temporal relations in the data. This study demonstrates the great potential of PINNs for spectropolarimetric inversions, with outlooks for future LTE and non-LTE inversions applications.
Yuta	Notsu	CU Boulder / LASP / NSO	Yuta Notsu (1), A. Kowalski (1), H. Maehara (2), K. Namekata (3), K. Hamaguchi (4), T. Enoto (3), I. Tristan (1), S. Hawley (5), J. Davenport (5), S. Honda (6), K. Ikuta (7), S. Inoue (3), K. Namizaki (3), D. Nogami (3), K. Shibata (3)	(1)CU Boulder/LASP/NSO, (2)NAOJ, (3)Kyoto Univ, (4) NASA/GSFC&UMBC, (5) Univ of Washington, (6) Univ of Hyogo, (7) Univ of Tokyo	Blue wing asymmetries in Balmer lines and possible mass ejections during mid M dwarf flares	Flares are releases of magnetic energy in the solar/stellar atmosphere. During some M dwarf flares, chromospheric line profiles show blue wing asymmetries, which may provide clues for the early phases of stellar coronal mass ejections (CMEs), but this is still controversial. We conducted 31-nights of simultaneous optical spectroscopic and photometric observations of mid M dwarf flare stars, using APO 3.5m and SMARTS 1.5m telescopes. Among the 41 detected flares, 7 flares showed clear blue wing asymmetries in Balmer lines, with various correspondences in flare properties. The line-of-sight velocities of the blue-shifted components range from -73 to -122 km s^-1. Assuming that the blue-shifts were caused by prominence eruptions, the mass of upward moving plasma was estimated to be 10^15 to 10^19g, which are roughly on the relation between flare energy and erupting mass expected from solar CMEs. In contrast, the kinetic energies of these events are roughly two orders of magnitude smaller than the relation expected from solar CMEs, as also shown in previous M-dwarf CME studies. These low kinetic energies may be explained by assuming a difference in velocities between prominence eruptions and CMEs, though further investigation on the evolutions of these stellar chromospheric and coronal eruptions is needed. In this presentation, we introduce these results and discuss prospects for further multi-wavelength observations and collaborations with modeling studies.
Willow	Reed	LASP/CU Boulder	Willow Reed, Julie Barnum, Gabriel Moraga, Gabi Gonzalez	Laboratory for Atmospheric and Space Physics (LASP)	The Boulder Solar Alliance REU: a multi-institute approach to undergraduate research	The Boulder Solar Alliance Research Experience for Undergraduates (BSA REU) is a long-established program within the Boulder solar and space science community.  Funded by the National Science Foundation, the BSA REU's primary goal is to introduce students to authentic research in solar and space physics, focusing on those with limited access to research opportunities at their home institutions. Now in our 18th year, we are looking to involve members of the BSA professional community who may not be familiar with the program. There are several opportunities to support this program, including giving lectures, participating in professional development sessions, and being a mentor or co-mentor to a participating student.  By having the program span multiple research institutions across the BSA, we are able to expose students to different ways solar and space physics research is conducted. In addition, the BSA REU coordination team cultivates a sense of community not only within the student cohort, but with mentors across these different institutions. This presentation will focus on broader impacts the program has had on the scientific community, how the support of the BSA professional community is vital to the program's success, and ways to be involved.
Cole	Tamburri	NSO; CU Boulder; LASP	Cole Tamburri (1,2,3), Adam Kowalski (1,2,3), Gianna Cauzzi (1), Alexandra Tritschler (1), Maria Kazachenko (1,2,3), Rahul Yadav (1), Ryan French (1), Yuta Notsu (1), Isaiah Tristan (1,2,3)	(1) National Solar Observatory; (2) University of Colorado Boulder; (3) Laboratory for Atmospheric and Space Physics	Constraining flare-time electron density, turbulent velocity, and the magnitude of the quadratic Stark effect with 1D radiative-hydrodynamic simulations and data from DKIST/ViSP	Observations from the NSF's Daniel K. Inouye Solar Telescope (DKIST) operated by the NSO provide novel diagnostics to improve our understanding of solar flares.   Specifically, spectra from the Visible Spectropolarimeter (ViSP) provide unique and timely opportunities for us to explain the mechanisms relevant to chromospheric lines such as the broad Balmer series and narrow Ca II lines observed in spectra of red dwarf star flares. Until now, sparse solar data have lacked sufficient spectral coverage to provide an unambiguous explanation for differences in the broadening of these lines, which also have been noted in spectra of solar flares. State of the art radiative hydrodynamic models are now available for interpreting optically thick chromospheric flare lines.  We leverage these new capabilities and investigate solar observations of the GOES class C6.7 solar flare SOL2022-08-19T20:31 from the ViSP and Visible Broadband Imager (VBI) at DKIST.  We analyze the spectral evolution in the chromospheric Ca II H 396.8 nm and H-epsilon 397.0 nm lines from ViSP observations and use VBI data to associate spectral data with their position within flare ribbons.   We use the F-CHROMA grid of radiative-hydrodynamic (RHD) RADYN models extended with the RH code to simulate Ca II H and H-epsilon with updated broadening prescriptions.  From these 1D models, we constrain parameters such as electron density, turbulent velocity, and the magnitude of the quadratic Stark effect, which are all important in chromospheric line broadening.   We investigate the differences in the emission line profiles of Ca II H at different spatial locations across the flare ribbon and compare the spectra at distinct physical locations to different time-steps in the simulation  Finally, we discuss what we learn from the remaining discrepancies in the shape of the Ca II H line and simultaneous evolution of Ca II H and H-Epsilon between the simulations and observations.
Amanda	White	Alumna of CU/NSO	Amanda White (1, 2), David Harrington(2)	(1) Cu Boulder, APS (2) NSO	Understanding polarization accuracy: the effect of mirror coating non- uniformity on instrument polarization	Astronomical mirror coatings are often metals protected by multiple layers of dielectrics. Varying the thickness and layering of dielectrics causes a significant dependence on the polarization properties (retardance, diattenuation, and depolarization) of reflected light across all wavelengths. Polarization further varies with angle of incidence and mirror shape.