AUTHOR=Frass-Kriegl Roberta , Broche Lionel Marc , Ginefri Jean-Christophe , Ladd Mark E. , Roat Sigrun , Sarracanie Mathieu , Winkler Simone Angela S. , Laistler Elmar TITLE=Editorial: Innovations in MR hardware from ultra-low to ultra-high field JOURNAL=Frontiers in Physics VOLUME=10 YEAR=2022 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2022.1015289 DOI=10.3389/fphy.2022.1015289 ISSN=2296-424X