LAUSR

Abstract The auroral oval is a well-established concept, introduced more than five decades ago. The Alfvenic oval, on the other hand, is a very recent concept, which has been revealed in both observational and numerical studies. This is the first review of the global Alfvenic oval, while also defining primary, secondary and tertiary layers of the Alfvenic oval. The focus lies on the large-scale dynamic properties of the global Alfvenic oval in relation to the AE index, substorm phases, storm phases and solar wind/IMF conditions. Statistical data recorded above and below the nominal auroral acceleration region are reviewed, together with results from global simulation studies that have reproduced the Alfvenic oval. The Alfvenic oval's relation to the auroral oval is also reviewed. This review demonstrates that the Alfvenic oval is well enough defined and investigated to give it its name, and it demonstrates that our understanding allows for the prediction of the Alfvenic oval under various conditions.