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Title: Plasma target output from a magnetically augmented, gas-injected, washer-stack plasma gun

Journal Article · · Rev. Sci. Instrum.; (United States)
DOI:https://doi.org/10.1063/1.1136871· OSTI ID:7037433

This article describes a new washer-stack gun design developed for the application of plasma target production for the startup of neutral-beam trapping in a fusion research magnetic confinement system. The gun is a Mo anode type that is D/sub 2/ injected and has an auxiliary pulsed magnet for control of plasma-flux mapping. One of the principal features of 2--10-ms duration pulses for gun operation in a suitable magnetic field is the formation of an arc column along magnetic field lines from the gun's central cathode electrode to the vacuum chamber walls (at common anode potential). The primary power output from a 5.0-cm-i.d. gun is typically carried along this arc column by a stream of approximately 2000 A of 50--250-eV electrons. This primary stream of relatively low-density energetic electrons efficiently ionizes the injected gas, forming a quasi-dc source of denser secondary plasma of approx.10/sup 13//cm/sup 3/ at a few eV, which is able to flow or diffuse away along a somewhat larger column of magnetic field lines. In plasma-target production tests on a test stand, a gun operated at a D/sub 2/ gas flow of 22 Torr ls/sup -1/ yielded 250 A of equivalent plasma flow.

Research Organization:
Lawrence Livermore National Laboratory, University of California, Livermore, California 94550
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
7037433
Journal Information:
Rev. Sci. Instrum.; (United States), Vol. 53:11
Country of Publication:
United States
Language:
English