Guest Editorial The Fifteenth Special Issue on High-Power Microwave Generation

The publication this year of the Fifteenth Special Issue on High-Power Microwave Generation continues a tradition in the field dating back to 1985. While the editors are concerned with the somewhat sparse selection of papers in this issue, the diversity of authorship both geographically and across research institutions is gratifying. The body of work represented by this volume emphasizes a clear continuation, in fact acceleration, of the use computational tools, which has represented a consistent trend in recent issues. Most notable are Particle in Cell (PIC) codes, which have enabled the optimization and virtual prototyping of a variety of High Power Microwave (HPM) sources. The overwhelming success of modern computational tools has all but eliminated the need for empirical iteration in the hardware realization of a given source design. Instead, any iteration proceeds during a virtual, numerical design process, and the final design is the only one built, saving both time and money.