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| Paper: |
Observations of Supersonic Downflows near the Umbra-Penumbra Boundary of Sunspots as Revealed by Hinode |
| Volume: |
455, 4th Hinode Science Meeting: Unsolved Problems and Recent Insights |
| Page: |
75 |
| Authors: |
Louis, R. E.; Rubio, L. R. B.; Mathew, S. K.; Venkatakrishnan, P. |
| Abstract: |
High resolution spectropolarimetric observations by
Hinode have revealed the existence of supersonic downflows at
the umbra-penumbra boundary of 3 sunspots (Louis et al. 2011). These
downflows are observed to be co-spatial with bright penumbral
filaments and occupy an area greater than 1.6 arcsec2. They are
located at the center-side penumbra and have the same polarity as the
sunspot which suggests that they are not associated with the Evershed
flow. In this paper we describe the supersonic velocities observed in
NOAA AR 10923 and discuss the photospheric as well as chromospheric
brightenings that lie close to the downflowing areas. Our observations
suggest that this phenomenon is driven by dynamic and energetic
physical processes in the inner penumbra which affect the chromosphere,
providing new constraints to numerical models of sunspots. |
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