The Rise of Active Region Flux Tubes in the Turbulent Solar Convective Envelope

ORAL

Abstract

We use a thin flux tube model in a rotating spherical shell of turbulent convective flows computed separately from an existing 3D global simulation to study how active region scale flux tubes rise buoyantly from the bottom of the convection zone to near the solar surface. We investigate initial toroidal flux tubes at the base of the convection zone with field strengths ranging from 15 kG to 100 kG at initial latitudes ranging from 2 to 40 degrees. We find that the dynamic evolution of the flux tube changes from magnetic buoyancy dominated to convection dominated as we decrease the initial field strength from 100 kG to 15 kG. The mean properties of the final emerging loops with an initial field strength of 100 kG are in agreement with previous thin flux tube models in the absence of convection, whereas at low field strengths of 15 kG, the properties of the emerging loops are significantly changed. With convection, the rise times are drastically reduced, the loops are able to emerge at low latitudes, the majority of the emerging loops show tilt angles of the proper sign, and also show a field strength asymmetry consistent with the observed morphological asymmetry of active regions. We discuss the implications of these results with regard to the field strength of the dynamo generated large-scale toroidal magnetic field at the base of the solar convection zone.

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Authors

  • Maria Weber

    High Altitude Observatory and Colorado State University

  • Andrew Polemi

    Utah State University, Brigham Young University, University of Pennsylvania, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, High Altitude Observatory, University of Colorado at Boulder, Massachutes Institute of Technology, Utah Valley University, University of New Hampshire, Applied Physics Laboratory, Johns Hopkins University, University of Montana, Southwest Research Institute, University of Southern California, Lockheed Martin Advanced Technology Center, University of Chicago, Massachusetts Institute of Technology, SciPrint.org, Centre National de la Recherche Scientifique, Colorado State University, V. Alecsandri College, Bacau, Romania, Colorado School of Mines, National Renewable Energy Laboratory, Utah State University, Department of Physics, Brigham Young University, Provo, Huntsman Cancer Institute, Brigham Young University - Idaho, University of Arizona, Florida State University, Weber State University, Brigham Young University - Provo, New Mexico State University, Colorado State University, Fort Collins, CO 80523

  • Andrew Polemi

    Utah State University, Brigham Young University, University of Pennsylvania, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, High Altitude Observatory, University of Colorado at Boulder, Massachutes Institute of Technology, Utah Valley University, University of New Hampshire, Applied Physics Laboratory, Johns Hopkins University, University of Montana, Southwest Research Institute, University of Southern California, Lockheed Martin Advanced Technology Center, University of Chicago, Massachusetts Institute of Technology, SciPrint.org, Centre National de la Recherche Scientifique, Colorado State University, V. Alecsandri College, Bacau, Romania, Colorado School of Mines, National Renewable Energy Laboratory, Utah State University, Department of Physics, Brigham Young University, Provo, Huntsman Cancer Institute, Brigham Young University - Idaho, University of Arizona, Florida State University, Weber State University, Brigham Young University - Provo, New Mexico State University, Colorado State University, Fort Collins, CO 80523