Journal Highlights

Ground-based solar monitoring and energetic particle event warning

Editor’s Highlight—


The Mauna Loa Solar Observatory (MLSO) located on a mountain top in Hawaii, USA, uses an instrument called K-Cor that creates artificial eclipse images for daily observations of the sunlight scattered by electrons in the inner solar corona. The polarized light from the solar limb is processed by K-Cor to provide information on the density and magnetic field of the Sun's corona. This paper presents a simple algorithm that has been developed to detect the onset of coronal mass ejections (CMEs) using ground-based observations from the observatory. Fast CMEs moving through the lower corona have been associated with significant solar energetic particle events, which with high enough flux can inhibit polar communications at Earth and be dangerous for astronauts and for airline crew and passengers traveling polar routes. The new algorithm automatically recognizes CMEs in MLSO K-Cor images in near real time while the eruption is still forming. The authors demonstrate that their observations and detection algorithms can provide advanced warning (1 to 3 hours) of fast CMEs moving through the inner corona. Currently bright CMEs are the most easily detected. The authors propose further work to warn of less bright CMEs more typical of solar minimum. This promising detection scheme is limited by cloudy weather conditions, limited observing time at a single observatory during daytime hours. They also note that daily observing duration is similar to that for solar observing spacecraft that must maintain contact with the NASA deep space network.