Sangam: A Confluence of Knowledge Streams

3D electron density distribution in the solar corona during solar minima: assessment for more realistic solar wind modelling

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dc.creator de Patoul, Judith
dc.creator Foullon, Claire
dc.creator Riley, Pete
dc.date 2015-11-23T10:06:37Z
dc.date 2015-11-17
dc.date 2015-11-23T10:06:37Z
dc.identifier Vol. 814 (1), article 68
dc.identifier 10.1088/0004-637X/814/1/68
dc.identifier http://hdl.handle.net/10871/18739
dc.identifier 1538-4357
dc.identifier 1538-4357
dc.identifier The Astrophysical Journal: an international review of astronomy and astronomical physics
dc.description Published
dc.description Article
dc.description © 2015. The American Astronomical Society. All rights reserved. Article published in The Astrophysical Journal, Volume 814, Number 1
dc.description Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from the last two recent minima of solar activity (1996–1997 and 2008–2010), devoid of coronal mass ejections. The goals are to derive the 4D electron density distributions in the corona by applying a newly developed time-dependent tomographic reconstruction method and to compare the results between the two solar minima and with two magnetohydrodynamic models. First, we confirm that the values of the density distribution in thermodynamic models are more realistic than in polytropic ones. The tomography provides more accurate distributions in the polar regions, and we find that the density in tomographic and thermodynamic solutions varies with the solar cycle in both polar and equatorial regions. Second, we find that the highest-density structures do not always correspond to the predicted large-scale heliospheric current sheet or its helmet streamer but can follow the locations of pseudo-streamers. We deduce that tomography offers reliable density distributions in the corona, reproducing the slow time evolution of coronal structures, without prior knowledge of the coronal magnetic field over a full rotation. Finally, we suggest that the highest-density structures show a differential rotation well above the surface depending on how they are magnetically connected to the surface. Such valuable information on the rotation of large-scale structures could help to connect the sources of the solar wind to their in situ counterparts in future missions such as Solar Orbiter and Solar Probe Plus.
dc.language en
dc.publisher American Astronomical Society
dc.relation http://stacks.iop.org/0004-637X/814/68
dc.relation http://iopscience.iop.org/0004-637X
dc.subject electron density distribution
dc.subject solar corona
dc.subject solar wind
dc.title 3D electron density distribution in the solar corona during solar minima: assessment for more realistic solar wind modelling
dc.type Article


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