The Sun Watcher with Active Pixels and Image Processing (SWAP) instrument onboard ESA’s PRoject for On Board Autonomy 2 (PROBA2) has provided the first uncompressed, high-cadence, continuous, large field-of-view observations of the extended extreme ultraviolet (EUV) corona for over a complete solar cycle. It has helped shape our understanding of this previously understudied region, and pioneered research into the middle corona. In this article we present a review of all publications that have utilized these observations to explore the extended EUV corona, highlighting the unique contributions made by SWAP. The review is broadly divided into three main sections of SWAP-based studies about: i) long-lived phenomena, such as streamers, pseudo-streamers, and coronal fans; ii) dynamic phenomena, such as eruptions, jets, EUV waves, and shocks; iii) coronal EUV emission generation. We also highlight SWAP’s imaging capabilities, techniques that have been applied to observations to enhance the off-limb observations, and its legacy.
- Corona, structures
- Coronal mass ejections, initiation and propagation
- Coronal mass ejections, low coronal signatures
- Instrumentation and data management
- Prominences, formation and evolution
- Radio bursts