title:    Chromospheric and transition region fine structures in observations
speaker:  J. Koza

Abstract

High resolution observations show that the solar chromosphere and
transition region are pervaded with thread-like structures
traditionally called spicules, fibrils, mottles, macrospicules,
etc. displaying rapid evolutionary changes. These elongated jets are
genetically linked with magnetic field governing all important
dynamical processes in outer solar atmosphere. This talk reviews the
latest advances in understanding of these chromospheric and transition
region fine structures achieved by observations. The talk is a
pictorial survey of the state of the art in imaging, spectroscopy, and
spectropolarimetry of the fine structures achieved by leading ground
based telescopes and space observatories. This gallery documents an
enormous complexity of the fine structures determined by the dominance
of ubiquitous magnetic field in outer solar atmosphere. For each
particular observation we attempt to highlight a key achievement
advancing our understanding. Observations clearly evidence that the
motion and dynamics of the fine structures correspond to the real mass
motion. A striking regularity was found in top motions of type I
spicules and dynamic fibrils which follow parabolic trajectories
propelled by some driver reducing solar gravity along their
trajectories. This is very indicative for magneto-acoustic shocks
propagating along inclined magnetic fluxtubes and lifting relatively
cool chromospheric plasma very high up to the hot coronal
environment. An important observational result is a first direct
spectropolarimetric measurement of spicular magnetic fields, which
lower limit is about 30 G.