Reflection of plasma ions from metals (and its use as a hyperthermal neutral beam source)
Reflection of ions as neutral atoms at energies below 100 eV has important implications for fusion and other technologies, and can form the basis of a s useful hyperthermal neutral beam. Experimental measurements of properties of such reflected atoms are presented. The apparatus developed for this work uses the acceleration of plasma ions across the shealth to a metal reflecting plate biased relative to the plasma potential. Ions are created by a coaxial RF (lower hybrid) plasma source with a 4 kG confining field. The plasma physics determining the characteristics of the ion current to the plate is discussed, and measurements of plasma parameters are presented. Measurements of the energy distribution of reflected atoms were made with a mass spectrometer/cylindrical mirror analyzer in experiments with several gases (Ar, Kr, Ne, N, O) and metals (Ta, Mo, steel, Al), at several reflection angles. Energy distribution measurements are compared to predictions of the Monte Carlo code TRIM, which uses the sequential binary collision model. The results differ from TRIM predictions that E{sub pk}/E{sub inc} is nearly constant with E{sub inc} in the observed with m{sub 2}/m{sup 1}. The observed behavior of E{sub pk}/E{sub inc} implies the projectile is reflected from a collective mass greater than m{sub 2} which increases as E{sub inc} decreases. An n-body simulation was written to examine the effects of simultaneous interaction with multiple target atoms.
- Research Organization:
- Princeton Univ., NJ (United States)
- OSTI ID:
- 5222361
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700460* -- Fusion Technology-- Heating & Fueling Systems
ACCELERATION
BEAM INJECTION
CHARGED PARTICLES
COMPARATIVE EVALUATIONS
DESIGN
ELEMENTS
ENERGY SPECTRA
EVALUATION
FLUIDS
Fu
Fuels-- (1992)
GASES
IONS
MASS SPECTROMETERS
MEASURING INSTRUMENTS
METALS
NEUTRAL ATOM BEAM INJECTION
NEUTRAL BEAM SOURCES
PLASMA
PLASMA ACCELERATION
REFLECTION
SPECTRA
SPECTROMETERS
THERMONUCLEAR REACTORS