Diagnostics Plan for the National Compact Stellarator Experiment

Abstract

The National Compact Stellarator Experiment (NCSX) is a stellarator-tokamak hybrid seeking to combine the good confinement, high beta and moderate aspect ratio of the tokamak with the quasi-steady-state operation and good stability properties of the stellarator. A preliminary list of measurement requirements, intended to satisfy the needs of the phased research plan, provides the basis for a full complement of plasma diagnostics. It is important to consider this full set, even at this early stage, to assess the adequacy of the stellarator design for diagnostic port access. The 3-D nature of the plasma is a measurement challenge, as is the necessity for high spatial resolution to assess the quality of magnetic surfaces. Other diagnostic requirements include the need 2 for re-entrant views that penetrate the cryostat, for a convenient e-beam probe for field line mapping, and for a diagnostic neutral beam for active spectroscopy.

Comparing PAH Availability from Manufactured Gas Plant Soils and Sediments with Chemical and Biological Tests. 1. PAH Release during Water Desorption and Supercritical Carbon Dioxide Extraction

“…Similarly, the other sample characteristics including elemental N and S, sand/silt/clay content, and total extractable hydrocarbons showed no strong correlation with the F values for the individual PAHs, and r 2 values were nearly all under 0.4. This lack of predictive capabilities using common soil parameters is in agreement with recent reports showing that knowledge of simple soil parameters (such as organic carbon) is not sufficient to predict the bioavailability of organic pollutants (5,14,16,(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39).…”

“…In addition, the molar C/H ratios for the CG samples (0.6- 1.1, except for CG-11 which is 2.3, but also contained particles that looked like coal) correspond much better with the five natural sediments and soils (0.6-0.8) than to the much higher ratios for the OG samples (2.4-6.3). Similarly, CG sample molar C/N ratios (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41) and the five natural soils and sediments (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) are substantially lower than those of the OG samples (78-93). Taken together, these analyses indicate that the aromatic nature of the carbon in the OG samples is much higher than for the CG samples and support the OG and CG carbon structures proposed earlier by others (3,40).…”

Mechanistic Characterization of Adsorption and Slow Desorption of Phenanthrene Aged in Soils

“…Therefore, the contribution of the slow desorbing fraction in solution to the total fraction of desorbed phenanthrene was assumed to be negligible, or to comprise the 'very slowly' desorbing fraction which, admittedly, could not be adequately assessed during a 21 day desorption kinetic study. Reported rate constants for the fast and slow desorbing fraction of HOCs in natural sorbents are in the range of 10 -5-10 -6 s -1 and 10 -7-10 -10 s -1 , respectively (24,(35)(36)(37). Our results show that the fast rate constants for phenanthrene desorption from soils were on the order of 10 -6-10 -7 s -1 after 30 days of sorption, but decreased by several orders of magnitude to 10 -8-10 -9 s -1 after 270 days (Table 4).…”

Physics Considerations in the Design of NCSX

“…Based on these physics considerations, a feasible engineering concept for the NCSX has been developed. [23] It provides the space and access provisions to augment the initial configuration with new capabilities, particularly diagnostics [24] and plasma-facing components, as needed in the course of the experimental program.…”