Solving Sunspot Mysteries: Photospheric and Chromospheric Dynamics of Sunspots Observed with New Solar Telescope

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Multi-wavelength observations of sunspots with the 1.6-meter telescope at Big Bear Solar Observatory (BBSO) in California and aboard NASA's IRIS spacecraft have produced new and intriguing images of high- speed plasma flows and eruptions extending from the Sun's surface to the outermost layer of the solar atmosphere, the corona. The 1.6m New Solar Telescope (NST) of Big Bear Solar Observatory allows us to investigate the structure and dynamics of sunspots with unprecedented spatial and temporal resolutions. The results of simultaneous observations of a sunspot in the photosphere with a broad-band TiO-line filter and in the chromospheric H-alpha line with Visible Imaging Spectrometer reveal previously unresolved features of the sunspot umbra and penumbra. In particular, the TiO data clearly demonstrate highly twisted dynamics of penumbral filaments and umbral dots and reveal strong shearing plasma flows in sunspot bridges, not explained by sunspot models. The high-resolution H-alpha spectroscopic data provide new views of the sunspot chromospheric dynamics, including the fine structure of oscillations and waves, penumbral jets, ubiquitous small-scale eruptions, and accretion flows in a form of dense plasma sheets. The diffraction-limited NST observations show that the sunspot dynamics is more complicated and much richer than it is described by the current sunspot models.

 

http://bbso.njit.edu/