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Title: The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode /SP Data

Abstract

Solar granules are bright patterns surrounded by dark channels, called intergranular lanes, in the solar photosphere and are a manifestation of overshooting convection. Observational studies generally find stronger upflows in granules and weaker downflows in intergranular lanes. This trend is, however, inconsistent with the results of numerical simulations in which downflows are stronger than upflows through the joint action of gravitational acceleration/deceleration and pressure gradients. One cause of this discrepancy is the image degradation caused by optical distortion and light diffraction and scattering that takes place in an imaging instrument. We apply a deconvolution technique to Hinode /SP data in an attempt to recover the original solar scene. Our results show a significant enhancement in both the convective upflows and downflows but particularly for the latter. After deconvolution, the up- and downflows reach maximum amplitudes of −3.0 km s{sup −1} and +3.0 km s{sup −1} at an average geometrical height of roughly 50 km, respectively. We found that the velocity distributions after deconvolution match those derived from numerical simulations. After deconvolution, the net LOS velocity averaged over the whole field of view lies close to zero as expected in a rough sense from mass balance.

Authors:
 [1]; ;  [2];  [3]; ;  [4]
  1. SOKENDAI (The Graduate University for Advanced Studies), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252–5210 (Japan)
  2. Max-Planck-Institut für Sonnensystemforschung (MPS), Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)
  3. Department of Science and Technology/Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo, 669–1337 Japan (Japan)
  4. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252–5210 (Japan)
Publication Date:
OSTI Identifier:
22679728
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 849; 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; ACCELERATION; AMPLITUDES; COMPUTERIZED SIMULATION; CONVECTION; DIFFRACTION; DISTRIBUTION; GRANULATION; HYDRODYNAMIC MODEL; IMAGE PROCESSING; MASS BALANCE; PHOTOSPHERE; PRESSURE GRADIENTS; SUN; VISIBLE RADIATION

Citation Formats

Oba, T., Riethmüller, T. L., Solanki, S. K., Iida, Y., Quintero Noda, C., and Shimizu, T.. The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode /SP Data. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8E44.
Oba, T., Riethmüller, T. L., Solanki, S. K., Iida, Y., Quintero Noda, C., & Shimizu, T.. The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode /SP Data. United States. doi:10.3847/1538-4357/AA8E44.
Oba, T., Riethmüller, T. L., Solanki, S. K., Iida, Y., Quintero Noda, C., and Shimizu, T.. Wed . "The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode /SP Data". United States. doi:10.3847/1538-4357/AA8E44.
@article{osti_22679728,
title = {The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode /SP Data},
author = {Oba, T. and Riethmüller, T. L. and Solanki, S. K. and Iida, Y. and Quintero Noda, C. and Shimizu, T.},
abstractNote = {Solar granules are bright patterns surrounded by dark channels, called intergranular lanes, in the solar photosphere and are a manifestation of overshooting convection. Observational studies generally find stronger upflows in granules and weaker downflows in intergranular lanes. This trend is, however, inconsistent with the results of numerical simulations in which downflows are stronger than upflows through the joint action of gravitational acceleration/deceleration and pressure gradients. One cause of this discrepancy is the image degradation caused by optical distortion and light diffraction and scattering that takes place in an imaging instrument. We apply a deconvolution technique to Hinode /SP data in an attempt to recover the original solar scene. Our results show a significant enhancement in both the convective upflows and downflows but particularly for the latter. After deconvolution, the up- and downflows reach maximum amplitudes of −3.0 km s{sup −1} and +3.0 km s{sup −1} at an average geometrical height of roughly 50 km, respectively. We found that the velocity distributions after deconvolution match those derived from numerical simulations. After deconvolution, the net LOS velocity averaged over the whole field of view lies close to zero as expected in a rough sense from mass balance.},
doi = {10.3847/1538-4357/AA8E44},
journal = {Astrophysical Journal},
number = 1,
volume = 849,
place = {United States},
year = {Wed Nov 01 00:00:00 EDT 2017},
month = {Wed Nov 01 00:00:00 EDT 2017}
}