Investigating Remote-Sensing Techniques to Reveal Stealth Coronal Mass Ejections

Eruptions of coronal mass ejections (CMEs) from the Sun are usually associated with a number signatures that can be identified in solar disc imagery. However, there cases which CME is well observed coronagraph data missing clear low-coronal counterpart. These events have received attention during recent years, mainly as result increased availability multi-point observations, and now known “stealth CMEs.” In this work, we analyze examples stealth CMEs featuring various levels ambiguity. All selected case studies produced large-scale detected by coronagraphs were at least one secondary viewpoint, enabling priori knowledge their approximate source region. To each event, apply several image processing geometric techniques aim to evaluate whether such methods provide additional information compared study “normal” intensity images. We able identify weak eruptive for all upon careful investigation remote-sensing data, noting differently processed images may needed properly interpret elusive observations. also find effectiveness strongly depends on propagation direction respect observers relative spacecraft separation. Being observe therefore forecast great importance context space weather, since occasionally counterparts so-called “problem geomagnetic storms.”