Coronal information from EUV disk spectral line intensities

Center of disk EUV line intensities from quiet and active regions are used for determining an analytical expression for the variation of temperature with height in the lower corona, including the corona-chromosphere transition region. This approach imposes two coronal temperature regimes in both quiet and active regions. In each case the lower temperature regime is a continuation of the transition region, reaching a maximum of about 1.4 million deg in the quiet and 1.7 million deg in the active region. In the quiet region the high temperature regime, assumed isothermal, has a temperature of about 2.4 million deg, and in the active region, about 4.2 million deg.