Blob Sizes and Velocities in the Alcator C-Mod Scrape-Off Layer

Abstract

A new blob-tracking algorithm for the GPI diagnostic installed in the outboard-midplane of Alcator C-Mod is developed. I t tracks large-amplitude fluctuations propagating through the scrape-off layer and calculates blob sizes and velocities. We compare the results of this method to a blob velocity scaling from a simple blob-model for sheath-connected blobs. We further present initial results from a fully three-dimensional blob model that features plasma resistivity as a free parameter.