AUTHOR=Chen Ye , Branlard Julien , Decking Winfried , Ding Yuantao , Liu Bo , Qiang Ji , Raubenheimer Tor , Walker Nicholas TITLE=Editorial: Global developments towards continuous-wave free-electron lasers JOURNAL=Frontiers in Physics VOLUME=11 YEAR=2023 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2023.1319861 DOI=10.3389/fphy.2023.1319861 ISSN=2296-424X