DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Experimental studies of the arc chamber short circuit failure mechanism on the DIII-D neutral beam system

Journal Article · · Fusion Engineering and Design

Here we report on efforts to improve performance and longevity of the Neutral Beam Injection (NBI) system by initiating a R&D program aimed at studying the most common failure mechanism for the ion sources. To this end a filament driven plasma chamber has been constructed with plasma parameters similar to the arc chamber of NBI ion sources. A preliminary report of an investigation into the most common failure is presented here: The failure mechanism observed during helium operations on DIII-D is the result of electrical breakdown of the insulation material that separates the filament plates from the anode. The fault is reproduced in a table top experiment analogous to the DIII-D NBI ion source in key parameters and proposals for amelioration of the issue are discussed.

Research Organization:
General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE
Grant/Contract Number:
FC02-04ER54698
OSTI ID:
1609185
Alternate ID(s):
OSTI ID: 2325550
Journal Information:
Fusion Engineering and Design, Vol. 146, Issue B; ISSN 0920-3796
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (4)

Giant ion sources of neutral‐beam injectors for fusion (invited) journal January 1990
Characteristics of the Berkeley multicusp ion source journal November 1979
Assessment of plasma parameters for the low activation phase of ITER operation journal November 2013
Self-sustained self-sputtering: a possible mechanism for the superdense glow phase of a pseudospark journal June 1995

Figures / Tables (7)