THE LOWER SOLAR ATMOSPHERE

Abstract. This “rapporteur ” report discusses the solar photosphere and low chromosphere in the context of chemical composition studies. The highly dynamical nature of the photosphere does not seem to jeopardize precise determination of solar abundances in classical fashion. It is still an open question how the highly dynamical nature of the low chromosphere contributes to first ionization potential (FIP) fractionation. Key words: Solar composition, solar atmosphere 1. Lower Atmosphere: Context This is a “consumer ” report on the lower solar atmosphere (photosphere and low chromosphere, the latter defined as the regime where hydrogen is not yet fully ionized) in its role as a provider of diagnostics for solar composition studies. The topic is reviewed by Solanki (1998), Judge and Peter (1998) and Grevesse and Sauval (1998) elsewhere in this volume. Let me begin by placing the lower atmosphere into its context. This meeting is unusual by combining research and researchers from the innermost to the outer-most solar reaches — a wide variety sketched broadly in Figure 1. g spectrap νh spectra νh spectra spectram R