edu.ucar.opensky::articles:24606 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T23:07:04.005353 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7m61ppd https://doi.org/10.5281/zenodo.1412824 https Related Software #1 HelioML/HelioML: HelioML 0.4.0 (2021-02-08) Measuring the magnetic origins of solar flares, coronal mass ejections, and space weather 2021-08-01T00:00:00Z publication https://n2t.org/ark:/85065/d7m61ppd https://doi.org/10.3847/1538-4357/ac081f Judge, Philip G. author Rempel, Matthias author Ezzeddine, R. author Kleint, L. author Egeland, Ricky author Berdyugina, S. V. author Berger, T. author Bryans, Paul author Burkepile, Joan R. author Centeno, Rebecca author de Toma, Giuliana author Dikpati, Mausumi author Fan, Yuhong author Gilbert, Holly author Lacatus, Daniela A. author UCAR/NCAR - Library publisher We take a broad look at the problem of identifying the magnetic solar causes of space weather. With the lackluster performance of extrapolations based upon magnetic field measurements in the photosphere, we identify a region in the near-UV (NUV) part of the spectrum as optimal for studying the development of magnetic free energy over active regions. Using data from SORCE, the Hubble Space Telescope, and SKYLAB, along with 1D computations of the NUV spectrum and numerical experiments based on the MURaM radiation-magnetohydrodynamic and HanleRT radiative transfer codes, we address multiple challenges. These challenges are best met through a combination of NUV lines of bright Mg ii, and lines of Fe ii and Fe i (mostly within the 4s-4p transition array) which form in the chromosphere up to 2 x 10(4) K. Both Hanle and Zeeman effects can in principle be used to derive vector magnetic fields. However, for any given spectral line the tau = 1 surfaces are generally geometrically corrugated owing to fine structure such as fibrils and spicules. By using multiple spectral lines spanning different optical depths, magnetic fields across nearly horizontal surfaces can be inferred in regions of low plasma beta, from which free energies, magnetic topology, and other quantities can be derived. Based upon the recently reported successful sub-orbital space measurements of magnetic fields with the CLASP2 instrument, we argue that a modest space-borne telescope will be able to make significant advances in the attempts to predict solar eruptions. Difficulties associated with blended lines are shown to be minor in an Appendix. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation