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Title: The Open Flux Problem

Abstract

The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field regions in the model should approximately correspond to coronal holes (CHs) observed in emission and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. In this study, we calculate both magnetohydrodynamic and potential field source surface solutions using 14 different magnetic maps produced from five different types of observatory magnetograms, for the time period surrounding 2010 July. We have found that for all of the model/map combinations, models that have CH areas close to observations underestimate the interplanetary magnetic flux, or, conversely, for models to match the interplanetary flux, the modeled open field regions are larger than CHs observed in EUV emission. In an alternative approach, we estimate the open magnetic flux entirely from solar observations by combining automatically detected CHs for Carrington rotation 2098more » with observatory synoptic magnetic maps. This approach also underestimates the interplanetary magnetic flux. Our results imply that either typical observatory maps underestimate the Sun’s magnetic flux, or a significant portion of the open magnetic flux is not rooted in regions that are obviously dark in EUV and X-ray emission.« less

Authors:
; ; ; ; ;  [1];  [2];  [3];  [4];  [5];  [6];  [7]
  1. Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States)
  2. Air Force Research Lab/Space Vehicles Directorate, 3550 Aberdeen Avenue SE, Kirtland AFB, NM (United States)
  3. Science and Exploration Directorate, NASA/GSFC, Greenbelt, MD 20771 (United States)
  4. W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)
  5. Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street B/252, Palo Alto, CA 94304 (United States)
  6. Department of Mathematical Sciences, Durham University, Durham, DH1 3LE (United Kingdom)
  7. Space and Atmospheric Electricity Group, Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading RG6 6BB (United Kingdom)
Publication Date:
OSTI Identifier:
22679762
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 848; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; BOUNDARY CONDITIONS; COMPUTERIZED SIMULATION; DATA ANALYSIS; EMISSION; EXTREME ULTRAVIOLET RADIATION; HELIOSPHERE; MAGNETIC FIELDS; MAGNETIC FLUX; MAGNETOHYDRODYNAMICS; PHOTOSPHERE; ROTATION; SOLAR CORONA; SOLAR WIND; SPACE; SUN; SURFACES; X RADIATION

Citation Formats

Linker, J. A., Caplan, R. M., Downs, C., Riley, P., Mikic, Z., Lionello, R., Henney, C. J., Arge, C. N., Liu, Y., Derosa, M. L., Yeates, A., and Owens, M. J., E-mail: linkerj@predsci.com. The Open Flux Problem. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8A70.
Linker, J. A., Caplan, R. M., Downs, C., Riley, P., Mikic, Z., Lionello, R., Henney, C. J., Arge, C. N., Liu, Y., Derosa, M. L., Yeates, A., & Owens, M. J., E-mail: linkerj@predsci.com. The Open Flux Problem. United States. doi:10.3847/1538-4357/AA8A70.
Linker, J. A., Caplan, R. M., Downs, C., Riley, P., Mikic, Z., Lionello, R., Henney, C. J., Arge, C. N., Liu, Y., Derosa, M. L., Yeates, A., and Owens, M. J., E-mail: linkerj@predsci.com. Tue . "The Open Flux Problem". United States. doi:10.3847/1538-4357/AA8A70.
@article{osti_22679762,
title = {The Open Flux Problem},
author = {Linker, J. A. and Caplan, R. M. and Downs, C. and Riley, P. and Mikic, Z. and Lionello, R. and Henney, C. J. and Arge, C. N. and Liu, Y. and Derosa, M. L. and Yeates, A. and Owens, M. J., E-mail: linkerj@predsci.com},
abstractNote = {The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field regions in the model should approximately correspond to coronal holes (CHs) observed in emission and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. In this study, we calculate both magnetohydrodynamic and potential field source surface solutions using 14 different magnetic maps produced from five different types of observatory magnetograms, for the time period surrounding 2010 July. We have found that for all of the model/map combinations, models that have CH areas close to observations underestimate the interplanetary magnetic flux, or, conversely, for models to match the interplanetary flux, the modeled open field regions are larger than CHs observed in EUV emission. In an alternative approach, we estimate the open magnetic flux entirely from solar observations by combining automatically detected CHs for Carrington rotation 2098 with observatory synoptic magnetic maps. This approach also underestimates the interplanetary magnetic flux. Our results imply that either typical observatory maps underestimate the Sun’s magnetic flux, or a significant portion of the open magnetic flux is not rooted in regions that are obviously dark in EUV and X-ray emission.},
doi = {10.3847/1538-4357/AA8A70},
journal = {Astrophysical Journal},
number = 1,
volume = 848,
place = {United States},
year = {Tue Oct 10 00:00:00 EDT 2017},
month = {Tue Oct 10 00:00:00 EDT 2017}
}