Authors: Michael Hahn (Columbia University), Mahboubeh Asgari-Targhi (Harvard-Smithsonian Center for Astrophysics), Daniel Wolf Savin (Columbia University)

We have measured line widths in active region coronal loops in order to determine whether the non-thermal broadening is anisotropic with respect to the magnetic field direction. These non-thermal velocities are caused by unresolved fluid motions. We studied spectra form the Extreme Ultraviolet Imaging Spectrometer on Hinode. These data were compared to a nonlinear force free magnetic field extrapolation based on data from SDO in order to determine the angle between the line of sight and the magnetic field and thereby infer anisotropy. We found that the non-thermal velocity tends to be greater in the parallel direction rather than the perpendicular direction. Wave-heating models can predict perpendicular non-thermal velocities caused by the transverse Alfven waves but usually do not include the effects of heating processes that can drive parallel flows. In order to compare model predictions with the observations, such models will need to incorporate heating-driven parallel flows. Our analysis also highlighted the importance of background sources. We found that emission lines that are commonly thought of as active region lines have a substantial emission contribution from temperatures more typical of the quiet Sun.