The purpose of the proposed work is to investigate emerging active regions and look for potential precursor indicators of their emergence. The discovery of a propagation time anomaly as a precursor to…

This is a federal grant awarded by the National Aeronautics and Space Administration (NASA) to the Smithsonian Astrophysical Observatory (SAO), a division of the Smithsonian Institution, for a project titled "Time-Distance Study of Emerging Active Regions Using HMI Observations". The grant's purpose is to investigate emerging active regions on the Sun and look for potential precursor indicators of their emergence, using data from NASA's Solar Dynamics Observatory (SDO) and the Solar and Heliospheric Observatory (SOHO) missions. The grant, valued at $295,881.27, will allow the SAO to apply its expertise in data processing and time-distance analysis to this research, with the goal of better understanding the Sun's activity cycle and the characteristics of active regions as they emerge. This grant is not associated with any set-aside designation.

The purpose of the proposed work is to investigate emerging active regions and look for potential precursor indicators of their emergence. The discovery of a propagation time anomaly as a precursor to the emergence of AR 10488 using a modified time-distance analysis of MDI observations has led to a flurry of studies on emerging regions. Since the initial paper (2011), several investigators have tried to reproduce these results, to apply that analysis to other active regions and to explain why such a precursor has so far only been seen in one occasion. Mission data: this proposal will draw extensively from two data sets produced by two missions of the helio-physics system observatory: primarily HMI on SDO, complemented by MDI on soho. Data analysis methodology: we propose to apply the PI's expertise in both precise and detailed data processing, and specifically in time-distance analysis to the puzzle of emergence precursors, using primarily HMI observations. We have a substantial set of observations to identify a significant number of "simple" and "well observed" emerging active regions. These are regions located close enough to the equator and emerging at times when the region is also close to the central meridian. Indeed, such regions allow US to both ensure data sets of high spatial resolution and to follow the regions with adequate spatial resolution before and after their emergence. We propose to adapt and apply the PI's time distance data analysis procedure to investigate the presence or absence of precursor indicators. The nitty-gritty details of the data processing seem to affect in still mysterious ways the detection (or the non-detection) of a precursor indicator. IT is therefore important to develop independent approaches to the analysis to confirm or not what in the analysis or the regions lead to the detection of a precursor indicator. Also, precursor indicators have so far not been observed for most emerging active regions. IT is therefore key to figure out which, if any, of the properties of the emerging region leads to the potential detection of such precursor indicator. We propose to carry out a systematic study of a large set of regions to derive statistically significant inferences of precursor indicator detectability. Relevance of the problem: this project will contribute to a better understanding of the sun's near-surface layers and the processes that drive its activity cycle. A key question that this work will contribute to answering is "how and why does the sun vary?" by studying emerging active regions and deriving either potential precursor indicators, or explaining why these precursors are present only in some specific cases, we expect to contribute to our understanding of the characteristics (like topology) of the active region as IT is about to emerge. A central question of heliospheric research is to understand the origin of solar magnetic fields. The sun exhibits 22-year cycles of global magnetic activity involving magnetic regions visible at the surface with very well-defined polarity rules, resulting in global scale magnetic patterns. Coexisting with these large-scale structures and concentrated active regions are ephemeral active regions and other compact and intense flux structures that emerge randomly over much of the solar surface forming a "magnetic carpet." the extension to the solar atmosphere of these changing fields at all scales creates coronal activity, which in turn is the source of space weather variability.