Resource Type

Delta f Monte Carlo Calculation Of Neoclassical Transport In Perturbed Tokamaks (open access)

Delta f Monte Carlo Calculation Of Neoclassical Transport In Perturbed Tokamaks

Non-axisymmetric magnetic perturbations can fundamentally change neoclassical transport in tokamaks by distorting particle orbits on deformed or broken flux surfaces. This so-called non-ambipolar transport is highly complex, and eventually a numerical simulation is required to achieve its precise description and understanding. A new delta#14;f particle code (POCA) has been developed for this purpose using a modi ed pitch angle collision operator preserving momentum conservation. POCA was successfully benchmarked for neoclassical transport and momentum conservation in axisymmetric con guration. Non-ambipolar particle flux is calculated in the non-axisymmetric case, and results show a clear resonant nature of non-ambipolar transport and magnetic braking. Neoclassical toroidal viscosity (NTV) torque is calculated using anisotropic pressures and magnetic fi eld spectrum, and compared with the generalized NTV theory. Calculations indicate a clear #14;B2 dependence of NTV, and good agreements with theory on NTV torque pro les and amplitudes depending on collisionality.
Date: April 11, 2012
Creator: Kimin Kim, Jong-Kyu Park, Gerrit Kramer and Allen H. Boozer
System: The UNT Digital Library
Chemical Facility Security: Issues and Options for the 112th Congress (open access)

Chemical Facility Security: Issues and Options for the 112th Congress

This report provides a brief overview of the existing statutory authority and the regulation implementing this authority. It describes several policy issues raised in previous debates regarding chemical facility security and identifies policy options for congressional consideration. Finally, legislation in the 112th Congress is discussed.
Date: June 11, 2012
Creator: Shea, Dana A.
System: The UNT Digital Library