Bibcode
DOI
Lites, B. W.; Leka, K. D.; Skumanich, A.; Martinez Pillet, V.; Shimizu, T.
Bibliographical reference
Astrophysical Journal v.460, p.1019
Advertised on:
4
1996
Citations
164
Refereed citations
123
Description
We present recent observations of quiet regions near the center of the
solar disk using the Advanced Stokes Polarimeter. These observations
reveal a component of the solar magnetic field heretofore unobserved:
isolated, small-scale (typically 1"-2" or smaller), predominantly
horizontal magnetic flux structures in the solar photosphere. These
features occur in isolation of the well-known, nearly vertical flux
concentrations usually seen in the photospheric "network." Hence we
ascribe this horizontal flux to the photospheric "internetwork." They
reveal themselves by the distinct signature of the Stokes Q and U
polarization profiles, which are symmetric about the line center. The
polarization signals are weak, with peak amplitudes typically
˜0.1%-0.2% of the continuum intensity in the resolved spectral
profiles, but they are well above the noise level of these observations
(≍0.05%). Such magnetic fields are weak (significantly less than
1000 G) and largely horizontal owing to the absence, or near absence, of
accompanying Stokes V polarization when observed at the center of the
solar disk. These horizontal field elements are often associated with
blueshifted Stokes line profiles, and they often occur between regions
of opposite polarity (but weak) Stokes V profiles. The horizontal
elements are short-lived, typically lasting ˜5 minutes. Our
observations suggest that we are viewing the emergence of small,
concentrated loops of flux, carried upward either by granular convection
or magnetic buoyancy. Even though these entities show weak field
strengths, they also seem to be fairly common, implying that they could
carry the order of 1024 Mx of magnetic flux to the surface on
a daily basis. However, further observational study is needed to
identify the specific nature of this phenomenon.