Overview of plasma accelerators

This is an overview of plasma accelerators. It is nor intended to he a detailed review of the field. [See E. Esarey et al.(1) for a nice recent review, numerous recent articles in Physical Review Letters, and excellent contributions to these proceedings for a relatively complete update on the latest state of current research.] Rather, the intent of this overview is to review the concepts of plasma accelerators and provide some context for the articles that follow. We begin with a brief tutorial section on plasma wakefield accelerators based on simple physical pictures. Then we briefly assess the start of the field and its current direction. In particular, we describe the key physics and technology issues for continuing the rapid progress the field has recently enjoyed. Some other roles for plasmas in accelerators besides serving as the accelerating structure are described. We conclude with some thoughts on the future prospects for plasma accelerators.