DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN Review | Direct submission with log-in | Request submission without log-in
Print this page

Print this page
Title	219: Establishing an experimental basis for plasma effects on magnetic islands
Name:	Todd Evans evans@fusion.gat.com	Affiliation:	General Atomics
Research Area:	ELM Control	Presentation time:	Not requested
Co-Author(s):	Jim Callen	ITPA Joint Experiment :	No
Description:	Measuring modifications of the properties of vacuum magnetic islands in H-mode discharges has not been possible due to diagnostic limitations in these highly rotating relatively hot plasmas. Understanding how the plasma transforms the width and internal structure of the islands (e..g, electric fields and flows) is essential for developing a theoretical basis for RMP ELM suppression that can be projected to ITER. The goal of this experiment is to use new imaging diagnostics (ECEI, SXRI, BESI, and high resolution CCD cameras) to obtain critical information on how edge magnetic islands are transformed by the plasma as the rotation and pressure is increased.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Start with inner wall limited plasmas and make measurements of magnetic islands with all available diagnostics (including fluctuation systems). Increase the power and torque to heat and rotate the plasma. If H-modes can not be obtained in this shape transition to a LSN ISS shape and apply various I-coil field combinations. Use all available diagnostics to search for islands. n=3 phase flipping will be use to modulate the islands. This is expected to increase the contrast for improved imaging.
Background:	In limited Ohmic and L-mode plasmas (e.g., Tore Supra, TEXTOR and TEXT) low edge temperatures have provided clear images of magnetic islands using visible emission line CCD cameras. Comparisons of these images with field line integration code calculations of vacuum magnetic islands have demonstrated that the plasma has very little if any affect on the size and locations of the islands under these operating conditions. Detailed measurements of the internal plasma properties of these islands have been made on TEXTOR, TEXT, CSTN-II and LHD using Langmuir probes, HIBPs and high resolution Thomson scattering. These reveal important processes that can have a significant impact on particle and energy confinement. This information is needed in H-mode plasmas to pin down how transport is affected by the RMPs and how ELMs are suppressed.
Resource Requirements:	--
Diagnostic Requirements:	--
Analysis Requirements:	--
Other Requirements:	--