Recent research has brought the application of microwaves from the classical fields of heating, communication, and generation of plasma discharges into the generation of compact plasmas that can be used for applications such as FIB and small plasma thrusters. However, these new applications bring with them a new set of challenges. With coverage ranging from the basics to new and emerging applications, Compact Plasma and Focused Ion Beams discusses how compact high-density microwave plasmas with dimensions smaller than the geometrical cutoff dimension can be generated and utilized for providing focused ion beams of various elements. Starting with the fundamentals of the cutoff problem for wave propagation in waveguides and plasma diagnostics, the author goes on to explain in detail the plasma production by microwaves in a compact geometry and narrow tubes. He then thoroughly discusses wave interaction with bounded plasmas and provides a deeper understanding of the physics. The book concludes with an up-to-date account of recent research on pulsed microwaves and the application of compact microwave plasmas for multi-element FIB. It provides a consolidated and unified description of the emerging areas in plasma science and technology utilizing wave-based plasma sources based on the author’s own work and experience. The book will be useful not only to established researchers in this area but will also serve as an excellent introduction to those interested in applying these ideas to various current and new applications.