Connecting the solar wind observed throughout the heliosphere to its origins in the sun S corona is one of the main goals of heliophysics. Understanding the basic physical processes driving solar…

This is a federal grant awarded by the National Aeronautics and Space Administration (NASA) to the Regents of the University of Michigan, Office of Research and Sponsored Projects, doing business as the University of Michigan. The $700,000 grant supports research to investigate and understand the stationary and time-dependent solar wind associated with low-latitude coronal holes, coronal streamers, and their open-closed flux surface interaction regions. The research aims to connect solar wind observations throughout the heliosphere to their origins in the Sun's corona, in order to develop physics-based, predictive space weather models. The grant does not have a set-aside designation. The University of Michigan is a top public research university that has received prior federal contract and grant awards from agencies such as the Department of Defense, National Institutes of Health, and Department of Energy to conduct cutting-edge research in areas like cybersecurity, fusion energy, and healthcare.

Connecting the solar wind observed throughout the heliosphere to its origins in the sun S corona is one of the main goals of heliophysics. Understanding the basic physical processes driving solar and heliospheric activity is crucial for developing physics-based, predictive space weather models. Our proposed research applies a synergistic approach to combine simulations and observations to investigate and understand the stationary and time-dependent solar wind associated with low-latitude coronal holes, coronal streamers, and their open-closed flux surface interaction regions. We propose to use the soho, stereo, hinode, and SDO imaging, spectroscopic, and magnetograph observations to provide the global solar context, detailed outflow properties and dynamics, and the magnetic field geometry of the source regions for the periods of solar wind under investigation. We will analyze in situ measurements from ACE and stereo to characterize the plasma and composition in different types of solar wind that provide a snapshot of the plasma conditions of their coronal origin. For select periods of streamer, pseudostreamer, and low-latitude coronal hole solar wind, we will conduct a comprehensive and multi-disciplinary, sunto- 1 AU examination of the remote and in situ data combined with new 3D numerical MHD simulations of magnetic reconnection in the observed source region configurations. (1) we will utilize standard heliospheric back-mapping techniques combined with the newly available Q-maps of the S-web structure calculated by pfss extrapolations from magnetogram synoptic data to identify the coronal sources of solar wind. The magnetograph, EUV, and spectroscopic data will be used to confirm the coronal source region context and to provide observational constraints to the initial magnetic field and plasma conditions for our MHD simulations. (2) we will perform new MHD modeling of solar wind source regions associated with periods of good solar imaging and spectroscopic coverage to constrain our model atmosphere densities, velocities, and temperatures. We will simulate different 3D reconnection scenarios based on the observed S-web topological features of the source region S magnetic field in order to model the consequences of this reconnection on the ionization of the solar wind. Magnetic reconnection at the cusps of helmet streamers and pseudostreamers will occur at the greatest heights whereas interchange reconnection at the separatrix and quasi-separatrix surfaces of the embedded closedflux systems that make up the S-web can occur over a range of lower heights and smaller spatial scales. (3) the predicted bulk plasma and field properties as well as the heavy ION charge state distributions within the model wind and reconnection-generated simulation outflows will be directly compared to the in situ observations of plasma, field and composition. We will quantify and compare the plasma and composition variability from our MHD simulation output with the corresponding predictions of the steady-state, expansion-factor model. We will then use the insights gained from these analyses to conduct a broad, systematic investigation of in situ solar wind, classified by source region type, for the signatures indicative of the dynamic formation and evolution characterized by our modeling results for each source region classification. Our project directly supports the solar orbiter and parker solar probe missions science objectives and addresses a number of the science goals identified in the solar and space physics decadal survey. Improving our understanding of the origins and evolution of low-latitude solar wind outflow and its variability will be crucial to determine the origins of the sun S activity and predict the variations of the space environment, determine the interaction of the sun with the solar system, and to discover and characterize fundamental processes that occur within the heliosphere.