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Abstract We begin here a series of papers examining the chromospheric and coronal properties of solar active regions. This first paper describes an extensive data set of images from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory curated for large-sample analysis of this topic. Based on (and constructed to coordinate with) the “Active Region Patches” as identified by the pipeline data analysis system for the Helioseismic and Magnetic Imager on the same mission (the “HARPs”), the “AIA Active Region Patches” (AARPs), described herein, comprise an unbiased multiwavelength set of FITS files downsampled spatially only by way of HARP-centered patch extractions (full spatial sampling is retained), and downsampled in the temporal domain but still able to describe both short-lived kinematics and longer-term trends. The AARPs database enables physics-informed parameterization and analysis using nonparametric discriminant analysis in Paper II of this series, and is validated for analysis using differential emission measure techniques. The AARP data set presently covers mid-2010 through 2018 December, is ≈9 TB in size, and is available through the Solar Data Analysis Center. 

Abstract A large sample of active-region-targeted time-series images from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), the AIA Active Region Patch database (Paper I) is used to investigate whether parameters describing the coronal, transition region, and chromospheric emission can differentiate a region that will imminently produce a solar flare from one that will not. Parameterizations based on moment analysis of direct and running-difference images provide for physically interpretable results from nonparametric discriminant analysis. Across four event definitions including both 24 hr and 6 hr validity periods, 160 image-based parameters capture the general state of the atmosphere, rapid brightness changes, and longer-term intensity evolution. We find top Brier Skill Scores in the 0.07–0.33 range, True Skill Statistics in the 0.68–0.82 range (both depending on event definition), and Receiver Operating Characteristic Skill Scores above 0.8. Total emission can perform notably, as can steeply increasing or decreasing brightness, although mean brightness measures do not, demonstrating the well-known active-region size/flare productivity relation. Once a region is flare productive, the active-region coronal plasma appears to stay hot. The 94 Å filter data provide the most parameters with discriminating power, with indications that it benefits from sampling multiple physical regimes. In particular, classification success using higher-order moments of running-difference images indicate a propensity for flare-imminent regions to display short-lived small-scale brightening events. Parameters describing the evolution of the corona can provide flare-imminent indicators, but at no preference over “static” parameters. Finally, all parameters and NPDA-derived probabilities are available to the community for additional research. 

Abstract Two new schemes for identifying field lines involved in eruptions, the r -scheme and q -scheme, are proposed to analyze the eruptive and confined nature of solar flares, as extensions to the original r m scheme proposed in Lin et al. Motivated by three solar flares originating from NOAA Active Region 12192 that are misclassified by r m , we introduce refinements to the r -scheme employing the “magnetic twist flux” to approximate the force balance acting on a magnetic flux rope (MFR); in the q -scheme, the reconnected field is represented by those field lines that anchor in the flare ribbons. Based on data obtained by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, the coronal magnetic field for 51 flares larger than M5.0 class, from 29 distinct active regions, is constructed using a nonlinear force-free field extrapolation model. Statistical analysis based on linear discriminant function analysis is then performed, revealing that despite both schemes providing moderately successful classifications for the 51 flares, the coronal mass ejection-eruptivity classification for the three target events can only be improved with the q -scheme. We find that the highly twisted field lines and the flare-ribbon field lines have equal average force-free constant α , but all of the flare-ribbon-related field lines are shorter than 150 Mm in length. The findings lead us to conclude that it is challenging to distinguish the MFR from the ambient magnetic field using any quantity based on common magnetic nonpotentiality measures. 

The space physics community continues to grow and become both more interdisciplinary and more intertwined with commercial and government operations. This has created a need for a framework to easily identify what projects can be used for specific applications and how close the tool is to routine autonomous or on-demand implementation and operation. We propose the Application Usability Level (AUL) framework and publicizing AULs to help the community quantify the progress of successful applications, metrics, and validation efforts. This framework will also aid the scientific community by supplying the type of information needed to build off of previously published work and publicizing the applications and requirements needed by the user communities. In this paper, we define the AUL framework, outline the milestones required for progression to higher AULs, and provide example projects utilizing the AUL framework. This work has been completed as part of the activities of the Assessment of Understanding and Quantifying Progress working group which is part of the International Forum for Space Weather Capabilities Assessment.