Preface to special issue: Private fusion research: Opportunities and challenges in plasma science

Recent years have seen a dramatic growth in privately funded fusion activities, which, in the US, are now at a scale comparable to the government sponsored program.Work in the private sector has been built on solid foundations laid down by years of publicly funded research but offers the potential to expand the field into new directions with a sharper focus on energy applications.While the two funding streams that support fusion research share the same underlying scientific principles, it is natural that the private and public sectors will have different perspectives on the challenges and opportunities in plasma science moving forward.This special topic collection explores future directions for our science in light of the expanded research base.The papers in the collection are of the type "Perspectives," which are intended to provide the authors' unique views on where the field is headed and promising strategies for progress.We believe that this set of papers can make a significant contribution to an ongoing dialog in the field and will help us take maximum advantage of the opportunities that this new circumstance offers.