Analytic Criteria for Power Exhaust in Divertors due to Impurity Radiation

Present divertor concepts for next step experiments such ITER and TPX rely upon impurity and hydrogen radiation to transfer the energy from the edge plasma to the main chamber and divertor chamber walls. The efficiency of these processes depends strongly on the heat flux, the impurity species, and the connection length. Using a database for impurity radiation rates constructed from the ADPAK code package, we have developed criteria for the required impurity fraction, impurity species, connection length and electron temperature and density at the mid-plane. Consistent with previous work, we find that the impurity radiation from coronal equilibrium rates is, in general, not adequate to exhaust the highest expected heating powers in present and future experiments. As suggested by others, we examine the effects of enhancing the radiation rates with charge exchange recombination and impurity recycling, and develop criteria for the minimum neutral fraction and impurity recycling rate that is required to exhaust a specified power. We also use this criteria to find the optimum impurity for divertor power exhaust.Comment: Preprint for the 11th PSI meeting, Adobe pdf with 14 figures, 15 page

Prevalence of antibiotic resistant pathogens in feral hogs of Texas

Fecal samples from feral hogs were collected (n=36) from four locations in Texas including Runnels, Haskell, Crane, and Sutton counties. Samples were analyzed for Escherichia coli populations, Salmonella spp. and Listeria spp. prevalence, and bacterial isolates were collected. Commercial microbroth dilution plates were used to establish antibiotic resistant profiles on the isolates. Non‐type specific E. coli was found in 91.7% of total samples (n=36) with isolates exhibiting the most common resistance (n=132 isolates) to Sulfisoxazole (46.2%), Tetracycline (2.2%), and Nalicixic acid (2.5%). Salmonella spp. was found in 27.7% of total samples with isolates (n=37) showing the most common resistance to Sulfisoxazole (29.7%) and Cefoxitin (2.7%). Listeria spp. was found in 22.2% of total samples with isolates (n=29) exhibiting the most common resistance to Lincomycin (89.6%), Daptomycin (68.9%), and Streptomycin (44.8%). This study provides evidence that feral hogs do harbor resistant pathogens that could be foodborne given the right opportunity. i

Does Chemical Leaf Burn of Double Crop Soybeans Reduce Yield?

Most farmers who have applied acifluorfen (sold as Blazer or Tackle) for postemergence control of broadleaf weeds in soybean fields are aware that leaf crinkling, bronzing, and necrosis can result. Despite this, studies in Kentucky, Illinois, Arkansas, and South Carolina have shown that full season soybeans have plenty of time to recover from leaf burn caused by this herbicide, and no yield losses have been found. However, double crop soybeans are usually planted much later than the full season crop. This delay in planting may reduce the time for plants to complete vegetative growth before beginning the seed production process. Therefore, double crop soybeans may be limited in their ability to recover from acifluorfen injury in time to produce as much grain as nonsprayed soybeans. Our objective was to determine if yields of double crop soybeans are reduced by leaf burn due to the use of acifluorfen

A System for Simulating Fluctuation Diagnostics for Application to Turbulence Computations

Present-day nonlinear microstability codes are able to compute the saturated fluctuations of a turbulent fluid versus space and time, whether the fluid be liquid, gas, or plasma. They are therefore able to determine turbulence-induced fluid (or particle) and energy fluxes. These codes, however, must be tested against experimental data, not only with respect to transport, but also characteristics of the fluctuations. The latter is challenging because of limitations in the diagnostics (e.g., finite spatial resolution) and the fact that the diagnostics typically do not measure exactly the quantities the codes compute. In this work, we present a system based on IDL{reg_sign} analysis and visualization software in which user-supplied ''diagnostic filters'' are applied to the code outputs to generate simulated diagnostic signals. The same analysis techniques as applied to the measurements, e.g., digital time-series analysis, may then be applied to the synthesized signals. Their statistical properties, such as rms fluctuation level, mean wave numbers, phase and group velocities, correlation lengths and times, and in some cases full S(k,{omega}) spectra can then be compared directly to those of the measurements

Magnetic stochasticity in gyrokinetic simulations of plasma microturbulence

Analysis of the magnetic field structure from electromagnetic simulations of tokamak ion temperature gradient turbulence demonstrates that the magnetic field can be stochastic even at very low plasma pressure. The degree of magnetic stochasticity is quantified by evaluating the magnetic diffusion coefficient. We find that the magnetic stochasticity fails to produce a dramatic increase in the electron heat conductivity because the magnetic diffusion coefficient remains small