The disturbing effect of probes inserted into edge plasmas of fusion devices

Abstract

With the exception of small, simple Langmuir probes, other probes used to diagnose the scrape-off plasma behind the limiter radius or separatrix in tokamaks are usually sufficiently large that they disturb the plasma they are measuring. A theory is presented for recovering the undisturbed plasma parameters from those measured by a large probe in a collisionless scrape-off layer.