Macroparticle Filters

Abstract

The most common and successful approach to deal with the infamous macroparticle issue is to utilize curved macroparticle filters. The principles of guiding arc plasma in filters are explained. A filter can be considered as a plasma optical system that takes the source plasma and transports it to a substrate, where an “image” of the source is produced. A solenoid is the simplest example of such a plasma optical system. The chapter contains a rather comprehensive review of plasma transport models as well as filter geometries. Many examples are illustrated. The different approaches are grouped. One way of classification is to consider filters using a duct with the magnetic filter coils surrounding it and filters of “open architecture,” characterized by openings through which the macroparticles can escape from the filter volume. In the open architecture, we utilize the fact that macroparticles tend to “bounce” from surfaces.