AAS 204th Meeting, June 2004
Session 20 Magnetic Fields
SPD Oral, Monday, May 31, 2004, 10:00-11:30am, 702

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[20.06] Diffraction Limited Spectro-Polarimetry at the Dunn Solar Telescope

K. Sankarasubramanian, T. R. Rimmele (National Solar Observatory), B. W. Lites (High Altitude Observatory)

The Diffraction Limited Spectro-Polarimeter (DLSP) is a collaborative project between the National Solar Observatory (NSO) and the High-Altitude Observatory (HAO). This new instrument, along with the high-order Adaptive Optics (AO-76) system (which is being developed at the NSO) has been used to measure magnetic fields on the solar photosphere at the highest spatial resolution (0.2~arcsec which is the diffraction limit of the DST at the 630.0nm wavelength). A few preliminary results obtained from the first observing run with this instrument are,

(1) The fine structures present inside the sunspot umbra (like the umbral dots) show upflows and reduced field strengths compared to the surrounding umbra.

(2) The sizes of these umbral fine structures goes down to the diffraction limit of the DST (about 0.2~arcsec). This result confirms that the instrument did achieve its full capability.

(3) There are small-scale convective up and down flows in the light bridges. The strength of these flow is about a km/sec. The field strengths are smaller in these regions compared to the surrounding umbra. At some places in the light bridges, the field strengths are as small as half of the umbral field strength.

(4) There are small-scale upflows in the inner penumbra of the observed sunspot. These regions coincide with the inner foot-point of the bright penumbral filaments as seen in the continuum intensity map. Some of these upflow regions also show a reduced field strength.

The author(s) of this abstract have provided an email address for comments about the abstract: sankara@nso.edu

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