Nonthermal Velocities in Different Temperature Regions of the Solar Lower Transition Region

Abstract

We analyze the relationship between nonthermal velocities derived from spectral lines of ions formed at different temperatures in the solar lower transition region, using spectra from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on board the Solar and Heliospheric Observatory (SOHO). We find a high degree of correlation among nonthermal motions arising at temperatures ranging from 3×10⁴ to 2.5×10⁵ K over 1" spatial scales in quiet-Sun regions. We discuss the implications of these results in terms of the physical nature of the transition region.