## Files in this item

FilesDescriptionFormat

application/pdf

9904576.pdf (4MB)
(no description provided)PDF

## Description

 Title: Beam-Ion Transport in Tokamaks: Thermalization in Large Orbit-Width Regime Author(s): Sager, Glenn Terry Doctoral Committee Chair(s): George Hunter Miley Department / Program: Nuclear Engineering Discipline: Nuclear Engineering Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Engineering, Nuclear Abstract: Comparison with the present results shows that the small orbit-width approximation introduces $\ge$5% errors in the density, parallel momentum, and energy moments when $\rho\sb{\theta}/L = 0.86$ in low-$Z\sb{\rm eff}$ plasmas. These results are observed for all source pitch-angles studied except the deeply passing sources, which are in good agreement ($\le$5%) with the small orbit-width model. A non-zero current, due to the large orbit-width of the trapped fast ions, is identified and related to, the superthermal alpha particle bootstrap "seed" current. In low-$Z\sb{\rm eff}$ plasmas, pitch-angle scattering is only important for marginally passing ion sources. Scattering into the trapping region causes substantial inward-directed transport that is not predicted in the convective model. Parallel momentum is reduced by $\sim$70%. For cases with marginally passing sources in higher $Z\sb{\rm eff}$ plasmas, transport into the trapping region scales linearly with scattering frequency $\nu\sb{\perp}.$ The results are sensitive to source localization in a layer at the trapping/passing boundary. Significant broadening of profiles is observed for cases with deeply trapped sources in higher $Z\sb{\rm eff}$ plasmas. Issue Date: 1998 Type: Text Language: English Description: 159 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998. URI: http://hdl.handle.net/2142/85942 Other Identifier(s): (MiAaPQ)AAI9904576 Date Available in IDEALS: 2015-09-28 Date Deposited: 1998
﻿