High-Resolution Observations of Magnetic Structures

High resolution observations in the ultra-violet spectral region are required in order to study the structure and energy balance of the solar atmosphere. Previous observations made with high spatial and spectral resolution show structure in the quiet and active atmosphere on the 1 arc sec scale. In addition to all pervasive non-thermal line broadening such observations show small regions where unusually large line widths and line shifts exist. The observations still required to investigate even the existence of wave heating modes are discussed, emphasising the importance of simultaneous measurements of line fluxes, electron densities and line profiles. The SOHO mission provides an excellent opportunity to resolve the issue of coronal heating.