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SoME‐UFo MC IRG No. 268245 PUBLISHABLE SUMMARY Marie Curie International Reintegration Grant No. 268245 SoME‐UFo – Solar Magnetic Eruptions: Understanding and Forecasting Scientific Coordinator: Academician Prof. G. Contopoulos Researcher: Dr. Emmanouil (Manolis) K. Georgoulis – [email protected] Project PostDoc: Dr. Konstantinos Tziotziou – [email protected] Host Institution: Research Center for Astronomy and Applied Mathematics (RCAAM) of the Academy of Athens, Athens, Greece Period Covered: Period 1 (1 November 2010 – 31 October 2012) Project webpage: http://astro.academyofathens.gr/people/georgoulis/SOME_UFO/ SUMMARY DESCRIPTION OF THE PROJECT OBJECTIVES: SoME‐UFo is a four‐year solar and space physics project aiming to (1) understand solar eruptions, and (2) help build a future capacity to predict them, thereby contributing to the forecasting of the variable, often adverse, space‐weather conditions. Targeted research goals will be achieved via a comprehensive, innovative analysis of solar vector magnetogram data combined with complementary information from other solar data sets. A breakdown of the project’s key scientific objectives is the following: [1] Achieve a thorough understanding of solar atmospheric magnetism. [2] Develop a physical insight into the triggering of solar magnetic eruptions. [3] Precisely calculate crucial physical parameters of solar eruptions and their host active regions. [4] Help build prediction‐ and geoimpact‐assessment capabilities of solar eruptions. DESCRIPTION OF WORK PERFORMED SINCE THE BEGINNING OF THE PROJECT: The first period of the project has been marked by meaningful, successful work toward all four of the above‐
stated objectives. The following summarizes this work per objective: In regards to [1], we (i) re‐examined and validated our existing method for resolving the intrinsic 180o azimuthal ambiguity in solar vector magnetograms inferred by the Zeefan effect, (ii) refined our method to infer magnetic connectivity in the solar atmosphere from photospheric‐only magnetograms, without prior knowledge of the overlaying three‐dimensional magnetic configuration, and (iii) made the first meaningful step toward a novel nonlinear force‐free (NLFF) three‐dimensional magnetic field extrapolation method. In regards to [2], we (i) defined robust thresholds for the magnetic free energy and the relative magnetic helicity budgets in active regions, above which regions become almost invariably eruptive, (ii) achieved a coherent, causal description of pre‐eruption evolution in active regions, and (iii) made concrete steps toward understanding the relation between the two distinct solar eruption manifestations, namely flares and coronal mass ejections (CMEs), by studying the timing between the two. In regards to [3], we (i) devised a robust, reliable, and computationally inexpensive method to calculate the instantaneous budgets of magnetic free energy and relative magnetic helicity in active regions and (ii) used this method to robustly infer the respective energy and helicity budgets of actual eruptions, at least in a few major eruption cases. In regards to [4], we (i) improved critically the calculation of the effective connected magnetic field strength, our flare‐predictive parameter of choice, and (ii) performed calculation of this parameter in a timeseries of space‐borne active‐region magnetograms acquired at an exceptionally high cadence, thus enabling study of the parameter’s behavior in unprecedented detail. Page 1 of 2 SoME‐UFo MC IRG No. 268245 DESCRIPTION OF MAIN RESULTS ACHIEVED SO FAR: • Validation of our existing azimuth disambiguation concept and algorithm that has resulted in the use of this tool by a number of colleagues and facilities worldwide. • Establishment of a reliable calculation of magnetic connectivity in the solar atmosphere by using only the observed photospheric vertical magnetic‐field component. • Preliminary development of a novel, operational NLFF magnetic field extrapolation method that does not require preprocessing of the non‐force‐free photospheric fields. • Reliable, robust, and routine calculation of magnetic free energy and relative magnetic helicity budgets in active regions. • Realistic calculation of magnetic‐energy and relative‐helicity contents of major solar eruptions. • Inference of the first magnetic energy‐helicity diagram of solar active regions with identifiable and well‐
interpreted thresholds for both physical parameters for eruptive active regions. • Settlement of a long‐standing debate regarding the existence or not of non‐neutralized (net) electric currents in the active‐region photosphere. • Extending the previous finding, discovery of a causal pre‐eruption evolution sequence in active regions, consistent with observations, and involving net currents, Lorentz forces, and magnetic/velocity shear. • Meaningful insight into the elusive flare‐CME connection, by presenting evidence that CME progenitors precede flare triggering. • Refined, improved calculation of the effective connected magnetic field strength in active regions, a parameter with very promising predictive capabilities, on a comprehensive magnetogram sample. • Discovery of fine details of the effective connected field strength pre‐eruption evolution, shedding light into a possible existence of solar eruption precursors. DISSEMINATION: • Six (6) grant‐supported refereed publications; two (2) grant‐supported proceedings publications. • Two (2) grant‐contributing refereed publications; one (1) grant‐contributing proceedings publication. • Six (6) grant‐supported conference participations featuring three (3) invited talks. • Four (4) grant‐contributing conference participations featuring two (2) invited talks. • Six (6) public invited talks on space weather for wider audiences, enhancing the project’s visibility. • An up‐to‐date project website. MILESTONES AND DELIVERABLES: Three (3) numerical codes developed and/or critically refined by the project are publicly available, including applicable documentation, in the project’s website. These are (i) our azimuth disambiguation code, (ii) the code performing calculation of the free magnetic energy and relative magnetic helicity budgets in active regions, and (iii) the code performing calculation of the effective connected magnetic field strength in active regions. Remaining milestones for Period 2 are to (a) finalize the NLFF field extrapolation method, (b) interpret eruption triggering, and (c) study / develop tools to assess the geoimpact (i.e., the implications for the terrestrial magnetosphere) of solar eruptions. EXPECTED FINAL RESULTS AND THEIR POTENTIAL IMPACT AND USE: The project will have fully achieved its objectives when the remaining milestones (a – c) have been reached and the respective finalized numerical codes (a, c) are made publicly available for use and citation by the interested researcher. The anticipated impact of a successful SoME‐UFo project will be two‐fold: in the scientific front, the project will have profoundly contributed to our understanding of the erupting Sun. In the practical front, it will have contributed with highly versatile numerical codes understanding and prediction of solar eruptions. This contribution encompasses a greater societal impact because it brings the space‐science community closer to optimizing space‐weather forecasting. Equally importantly, the project will have demonstrated the optimal way to achieve this benefit, which is by jointly advancing physical understanding with computational innovation. Page 2 of 2