Detailed SUMER observations of coronal loop footpoint dynamics

For the most part, the characteristics of heating in the open corona and in closed coronal loops are determined by observing the emitted plasma intensity as a function of position and comparing this with model calculations. There are also some efforts that include observed velocity and still others that use theoretical physical processes such as electrodynamic or turbulent heating, for example. With a view toward future modeling endeavors, we investigate the temporal behavior of the intensity and velocity of a magnetic loop footpoint as observed by SUMER on the Solar and Heliospheric Observatory (SOHO) spacecraft as part of SOHO/TRACE Joint Observing Program 72. We study these quantities in emission lines that were specifically chosen to span the temperature domain of the upper chromospheric and transition region plasmas (10⁵-10⁶ K). We discuss the implications of these observations, suggest improvements, and present some new avenues of exploration. The most significant result is the demonstration of the importance of including the measurement of velocity as a function of time in the loop footpoint region.