title: Wire tomography in the H-1NF heliac for investigation of fine structure of magnetic islands.
abstract: Electron beam wire tomography in the H-1NF heliac enables high resolution mapping of vacuum flux surfaces with minimal disruption of the plasma operations schedule. Recent experimental results have proven this technique to be a highly accurate and high resolution method for mapping vacuum magnetic islands. Islands of width as small as delta approximately 8 mm have been measured, providing estimates of the internal rotational transform of the island. Point-to-point comparison of the mapping results with computer tracing, in conjunction with an image warping technique, enables systematic exploration of magnetic islands and surfaces of interest. Recent development of a fast mapping technique significantly reduced the mapping time and made this technique suitable for mapping at higher magnetic fields. This article presents recent experimental results and associated techniques.
authors.affiliation: Plasma Research Laboratory, Research School of Physical Sciences and Engineering, The Australian National University, Canberra ACT 0200, Australia. santhosh.kumar@anu.edu.au
authors.forename: Santhosh T A
authors.initials: ST
authors.lastname: Kumar
authors.forename: Boyd D
authors.initials: BD
authors.lastname: Blackwell
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Harris
mesh_terms: D004574:Electromagnetic Fields; D007091:Image Processing, Computer-Assisted; D014057:Tomography, X-Ray Computed