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J.B. Lamb (University of Iowa, NSO/REU), A.A. Pevtsov (National Solar Observatory)
We study plasma flows in emerging active regions on the sun using data from the Michelson Doppler Imager (MDI) instrument on the SOHO satellite. Dopplergrams are compared with magnetograms and full continuum images in an effort to study the relationship between plasma flows and the magnetic and white light development of fifteen emerging active regions. This study focuses on the following flows in emerging active regions: (1) asymmetric flows from one polarity of the active region to the opposite polarity, (2) general trends of plasma flows before and immediately after emergence and (3) the emergence of Evershed flow with respect to penumbral development. The results of this study include (1) asymmetric flows found in three active regions. Two active regions exhibited flows from following to preceding polarity, confirming other observations of asymmetric flows. One active region exhibited a flow from the preceding to following polarity which has previously been theoretically predicted but until now has not been observed. (2) No consistent plasma flows were found before emergence. (3) After emergence, active regions exhibited overall downflows in the area around the region. (4) There also is some possible evidence for penumbra development before Evershed flow. This work was carried out through the National Solar Observatory Research Experiences for Undergraduates (REU) site program, which is co-funded by the Department of Defense in partnership with the National Science Foundation REU Program.
The author(s) of this abstract have provided an email address for comments about the abstract: joel-lamb@uiowa.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.