Chromospheric Vector Magnetic Field Measurements of Active Regions

Active regions, as the locations of complex and rapidly evolving magnetic fields, are also the source of many coronal mass ejections. The chromospheric magnetic field, being force-free, should provide direct insights into both the energy storage for solar energetic events, and possibly their trigger mechanism as well. In this talk I will review recent chromospheric vector field observations from the U. Hawai`i/Mees Solar Observatory Imaging Vector Magnetograph, obtained in the Na-I line at 589.6nm. The focus will be on the differences between the photosphere and chromosphere, and chromospheric field measurements relevant to CME production such as free energy storage and evolution prior to an energetic event.