Penumbral Dynamics and its Manifestation in the Overlying Chromosphere

Mature sunspots are usually surrounded by penumbra - a dense conglomerate of a random interlaced flux tubes with varying inclinations. High resolution observations show a fine sub-structure of penumbral filaments and new regularities in their dynamics. These regularities fit well our recent model of penumbra based on cascading reconnection events occurring in the system of non-collinear flux tubes. Each act of reconnection generates twist in the reconnected filaments and facilitates the onset of a screw pinch instability, consistent with the observations showing that individual filaments are cylindrical helices with a pitch/radius ratio providing their stability. In addition, the post-reconnection products produce a sling-shot effect that generates oblique shocks and leads to appearence of a lateral jets. Here we report high resolution (120-180 km) high cadence (15-30 sec) observations taken with the Solar Optical Telescope (SOT) on the Hinode satellite. Co-aligned multi-hour movies taken simultaneously in several wavelengths show detailed behavior of penumbra filaments and their effect on the overlying chromosphere. We confirm the ubiquitous nature of penumbral micro-jets recently discovered by SOT instrument (Katsukawa et al. 2007, AAS 210, 94.13), and present quantitative analysis of chromospheric jets based on our recent model of penumbra.