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Properties of Magnetic and Velocity Fields in and around Solar Pores

Authors :
and, Sankarasubramanian
Rimmele, Thomas
Source :
The Astrophysical Journal; November 2003, Vol. 598 Issue: 1 p689-699, 11p
Publication Year :
2003

Abstract

We studied the magnetic and velocity fields of four pores situated close to the disk center and its surrounding regions. We find the following results from our analysis: The velocity inside the pore is very close to zero, whereas there is a strong and narrow downflow around the pore. The vertical velocity gradient observed at the edge of the pore is stronger than the velocity gradient seen in intergranular lanes. Immediately surrounding these narrow downflows, normal granular convection is observed. This observation is consistent with the theoretical picture of an isolated flux tube embedded in a quiet region surrounded by a downflow driven by radiative energy losses. Needle-like structures were seen around the pore, with the head of the needle showing an upflow. The needle tail ends in the downflow surrounding the pore. Assuming the flow is horizontal in the body of the needle, the needle-like structures would represent a possible signature of circular flow system surrounding the pore. The radial extent of this observed flow system (which likely feeds the downflow around the pore) is about 10''. A pore with relatively large fill fraction shows a small upflow in the center surrounded by the downflow, whereas a pore with small fill fraction shows downflows throughout the pore. The asymmetries of the observed Stokes V profiles and their temporal variations are studied. We find temporal variations of V-profile asymmetries observed within pores on timescales of 5 minutes.

Details

Language :
English
ISSN :
0004637X and 15384357
Volume :
598
Issue :
1
Database :
Supplemental Index
Journal :
The Astrophysical Journal
Publication Type :
Periodical
Accession number :
ejs18554270