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Session 79 - Quiet Solar Photosphere and Chromosphere.
Oral session, Thursday, June 13

[79.04] Downflows in a Large EFR

G. A. Chapman, S. R. Walton (SFO/CSUN)

We observed an emerging flux region (EFR) on January 3, 1996 with the Video Spectra-Spectroheliograph (VSSHG) of the San Fernando Observatory (SFO). The region, BBSO no. 3652, was selected based on a BearAlert from the Big Bear Solar Observatory. Its position was N11 W11 at 2045 UT. The region grew from 110 microhemispheres (microhem) on the 3rd to 190 microhem on the 4th (W. Marquette, private communication, 1996). The observations, carried out over a 3-1/2 hour period beginning at 20:07 UT, consist of two-dimensional spectra of the 630.25 nm solar line analyzed for circular and linear polarization. The spectra are used to produce maps with 0.5 arc-sec pixels of the vector magnetic field, line-of-sight velocity and core and continuum intensity. A complete set of such images were produced every ten minutes during the observing period. From a preliminary analysis of about one-third of the data, we find that there is a persistent downflow located near the central portion of the EFR and very little upflow. Any possible upflows are either of low amplitude or cover a much smaller area than the downflow. The net downflow for the entire EFR is approximately 180-190 m/s. The strongest downflow, approximately 900-1000 m/s, occurs in the area of one of the larger sunspots in the EFR. This research was supported in part by NSF Grant ATM-9115111.

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