SMALL-SCALE, DYNAMIC BRIGHT BLOBS IN SOLAR FILAMENTS AND ACTIVE REGIONS

High-cadence high spatial resolution observations in Hα with the Swedish 1 m Solar Telescope on La Palma have revealed the existence of small-scale highly dynamic bright blobs. A fast wavelength tuning spectropolarimeter provides spectral information of these structures. The blobs slide along thin magnetic threads at speeds in the range from 45 km s−1 to 111 km s−1. The blobs have a slightly elongated shape and their lengths increase by a factor of three from close to half an arcsecond when they first appear until they disappear one to two minutes later. The brightest blobs show the highest speed. The widths of the Hα line emission of the blobs correspond to non-thermal velocities in the plasma less than 10 km s−1, which implies that they are not the result of shock-driven heating. The dynamic character of the bright blobs is similar to what can be expected from an MHD fast-mode pulse.