Publication Date:
2019-07-13
Description:
Magnetic fields in the Sun's outer atmosphere, the corona, control both solar-wind acceleration and the dynamics of solar eruptions. We present the first clear observational evidence of coronal magnetic nulls in off-limb linearly polarized observations of pseudostreamers, taken by the Coronal Multichannel Polarimeter (CoMP) telescope. These nulls represent regions where magnetic reconnection is likely to act as a catalyst for solar activity.CoMP linear-polarization observations also provide an independent, coronal proxy for magnetic expansion into the solar wind, a quantity often used to parameterize and predict the solar wind speed at Earth. We introduce a new method for explicitly calculating expansion factors from CoMP coronal linear-polarization observations, which does not require photospheric extrapolations. We conclude that linearly polarized light is a powerful new diagnostic of critical coronal magnetic topologies and the expanding magnetic flux tubes that channel the solar wind.
Keywords:
Solar Physics
Type:
MSFC-E-DAA-TN42508
,
Astrophysical Journal Letters (ISSN 2041-8205) (e-ISSN 2041-8213); 840; 2; L13
Format:
application/pdf
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