FIP effect measurements in the off-limb corona observed by SUMER on SOHO

Systematic differences between elemental abundances in the corona and in th e photosphere have been long acknowledged in the Sun; these abundance anoma lies are correlated with the first ionization potentials (FIPs) of the elem ents. This correlation is called FIP effect. Using spectra obtained from th e SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph on the spacecraft SOHO (Solar and Heliospheric Observatory), we investigate electron density, temperature and the abundance anomalies in the off-limb solar corona. In particular, we present the behaviour of the solar FIP effe ct with height above an active region observed at the solar limb, with K/Ar , Si/Ar and S/Ar ratios of lines present in the recorded UV spectra. We find that the K FIP bias seems to be higher than for the other low-FIP e lements, and that the Si and K FIP biases are dependent on the distance fro m the photosphere. Studying the Ne/Mg Line ratio in the active region, we a lso investigate the presence of the FIP effect in active region structures.