Measurements of fluctuations in the flux of runaway electrons to the PLT limiter

Technical Report · Thu Jul 01 00:00:00 EDT 1982

DOI:https://doi.org/10.2172/5183814· OSTI ID:5183814

Barnes, C W; Strachan, J D

Fluctuations in the flux of runaway electrons to the limiter have been measured during many PLT discharges. Oscillations at 60, 120, and 720 Hz are driven by variations in the vertical magnetic field which moves the plasma major radius. Fluctuations are seen in the range of 2 ..-->.. 20 kHz due to MHD magnetic islands which extend to the plasma surface. A continuous spectrum of fluctuations is observed up to 200 kHz which correlates with drift-wave turbulence. The magnitude of the driven fluctuations can be used to measure transport properties of the runaway electrons. The amplitude of electron motion due to the MHD and drift-wave oscillations, and hence a measure of the radial size of the instability, can be determined as a function of frequency. The slope of the frequency power spectrum of the drift-wave-induced fluctuations steepens with increasing runaway electron drift orbit displacement during the current drop at the end of the discharge, and as the power in the MHD oscillations increases. A magnetic probe was used to confirm the presence of oscillating magnetic fields capable of perturbing the electron orbits.

• Research Organization: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 5183814
• Report Number(s): PPPL-1916; ON: DE82018139; TRN: 82-017347
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLT DEVICES
RUNAWAY ELECTRONS
ELECTRON DRIFT
LIMITERS
MAGNETOHYDRODYNAMICS
OSCILLATIONS
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
FLUID MECHANICS
HYDRODYNAMICS
LEPTONS
MECHANICS
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
700104* - Fusion Energy- Plasma Research- Plasma Kinetics-Experimental- (-1987)