DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN Review | Direct submission with log-in | Request submission without log-in
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Title	132: Dissipation & Control of RE from ITER-like LSN targets
Name:	Nicholas Eidietis eidietis@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Disruption Mitigation	Presentation time:	Not requested
Co-Author(s):	Humphreys	ITPA Joint Experiment :	No
Description:	This experiment aims to produce runaway electron beams from vertically unstable ITER-like LSN targets and assess 2 scenarios: (1) The catch-all ITER case: Uncontrolled VUD or VDE - What is optimal level of (primary/secondary) impurity injection to minimize RE current before final RE loss? This is a race between CQ and vertical motion. - What is the condition for final RE loss in a VDE, particularly the location of the hot RE core? (2) Optimal ITER case: Time for setup - Assess if D3D coils set to ITER controllability limits can catch and hold RE from ITER-like LSN target. - Examine how that controllability improves as target moved towards the vessel neutral point	ITER IO Urgent Research Task :	Yes
Experimental Approach/Plan:	Start with ITER-like LSN target. 2012 data indicates very low densities aid RE production, so utilize optimal error field correction to enable ultra-low density operation. Kill the plasma using small argon pellet. For scenario 1, fire secondary MGI (neon, argon) into RE plateau during vertical motion. Vary quantity from shot-shot to alter RE current quench and observe point (if any) at which RE final loss current is mimimized. For scenario 2, set D3D vertical system to mimic controllability limits of ITER in-vessel coils. From shot-to-shot, move target plasma toward neutral point to assess if Z control can be established.
Background:	RE suppression in ITER is uncertain at best, and even if viable methods are developed, there will be times when they fail or do not have sufficient warning to react. Therefore, we must develop methods for minimizing the impact of a fully-formed RE channel, and have *validated* models of those scenarios. The first, and worst assumption is that the RE channel cannot be controlled by the ITER in-vessel coils (highly likely). In that case, the RE dissipation must be optimized to minimize the RE final loss. Note that the VDE speeds up if the CQ RE dissipation speeds up, so "as fast as possible" is not necesarily the best answer. On the other hand, we also want to experimentally verify the controllability of ta real RE beam using ITER-like Z control system, in order to validate models. In addition, given some warning, ITER may be able to reposition the target plasma closer to thte neutral point. we want to verify that the RE vertical controllability improves as the taret plasma is moved closer to the neutral point.
Resource Requirements:	- small argon pellet injector - MGI
Diagnostic Requirements:	- SXR (disruption mode) - Fast visible carmeras - full vessel IR camera - neutron counters
Analysis Requirements:	Use these RE VUD results to benchmark RE generation codes.
Other Requirements: