AAS Meeting #194 - Chicago, Illinois, May/June 1999
Session 59. Active Region Formation and Evolution
Solar, Oral, Tuesday, June 1, 1999, 2:30-4:00pm, Continental Ballroom C

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[59.07] The Photospheric Flow Near the Flare Locations of Active Regions

D. Choudhary (MSFC)

The flow pattern of flare locations in the active regions are observed by using the Tower Vector Magnetograph (TVM) of Marshall Space Flight Center. The line-center-magnetogram (LCM) technique (Giovanelli and Ramsay, 1971, IAU Symp, 43, 293) has been employed to determine the active region velocities. The LCM is based on finding the wavelength in the line profile where two opposite circularly-polarized Zeeman-Split components change sign. If the material in the magnetic field of different locations have relative line of sight velocities, their cross-over wavelength will be seen Doppler shifted. In order to use the LCM with TVM, a series of Stoke-V images as a function of wavelength are made and their cross-over wavelength at each pixel is determined. We have observed 12 active regions during June 25 to August 25, 1998. Four of these active regions (NOAA 8253, NOAA 8264, 8293 and NOAA 8307) show flare activity associated with the flux emergence and/or changes in magnetic shear during their disk passage. The cross-over wavelength of the locations of activities and the leading sunspot are seen to be different, implying the existence of the relative velocity between them. In one of the active regions (NOAA 8253), we clearly observe the blue shift associated with the emergence of new flux and magnetic shear. In the present paper, we examine the nature of material flow near the location of activity in these active regions.

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