AAS 204th Meeting, June 2004
Session 37 Solar Magnetic Fields and the Photosphere
SPD Poster, Tuesday, June 1, 2004, 10:00am-7:00pm, Ballroom

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[37.16] TRACE Observations of a Torsionally Rotating Sunspot Reversing Direction

R. W. Nightingale, T. R. Metcalf (Lockheed Martin Solar & Astrophysics Laboratory), J. R. Ullman (Henry M. Gunn High School, Palo Alto, CA)

For almost a week, starting on July 30, 2003, TRACE observed AR10421 in white light (WL), ultra-violet (UV), and extreme ultra-violet (EUV) passbands. Analysis of the photospheric WL images shows that the leading sunspot was torsionally rotating about the center of its umbra, in a clockwise direction on and before July 31 and counter-clockwise after a reversal of direction on August 1st. The sunspot appears to be fragmenting with clumps of small pores moving away toward the east during the first 2 days, followed by another clump that appears to be drawn into the sunspot after the rotational direction change on August 1st. Twisted coronal fans can be seen above the rotating sunspot in the EUV images on and after August 1st. Movies of this rather unique oscillatory behavior will be shown in 2 or more passbands, along with corresponding magnetogram data, as observed by SOHO/MDI.

This work has been supported by NASA, in part under the TRACE project at LMSAL (contract NAS5-38099) and in part under the MDI/SOHO project (NAG5-13261).

The author(s) of this abstract have provided an email address for comments about the abstract: nightingale@lmsal.com

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