Numerical determination of the ambipolar electric field in a stellarator-reactor plasma

1989 ◽  
Vol 42 (1) ◽  
pp. 133-151 ◽  
Author(s):  
W. D. D'Haeseleer ◽  
W. N. G. Hitchon ◽  
J. L. Shohet
Keyword(s):  
Electric Field ◽  
Parametric Study ◽  
Parameter Range ◽  
Confinement Time ◽  
Numerical Determination ◽  
Algebraic Condition ◽  
Order Of Magnitude ◽  
Numerical Parametric Study ◽  
Particle Confinement

A numerical parametric study of the radial ambipolar electric field in a stellarator reactor has been undertaken. With the numerical neoclassical code FLOCS (Flow Code for Stellarators), which is capable of handling both ions and electrons of all relevant kinetic energies, the radial ambipolar field (Er)AMB is determined from the algebraic condition that ion and electron fluxes are equal. As expected, the potential is of the same order of magnitude as the temperature. Somewhat surprisingly at first sight, however, the potential does not change much with the temperature (in the parameter range under consideration), being somewhat insensitive to moderate variations of T. An explanation for this behaviour is presented. Finally, the radial particle fluxes, consistent with the obtained (Er)AMB, and the particle confinement time are computed.

Numerical Determination of Fatigue Threshold from CTOD

2016 ◽  
Vol 258 ◽  
pp. 290-293
Author(s):  
Daniel Camas ◽  
Pedro Loureiro ◽  
Pedro Prates ◽  
Fernando Antunes
Keyword(s):  
Plastic Deformation ◽  
Parametric Study ◽  
Numerical Approach ◽  
Fatigue Threshold ◽  
Numerical Determination ◽  
Experimental Procedure ◽  
Material Parameters

The experimental procedure to obtain valid and comparable values of ΔKth is laborious and time consuming. The objective of this work is to determine ΔKth using a numerical approach. The CTOD is plotted versus load, and the fatigue threshold corresponds to the onset of plastic deformation. A parametric study was developed in order to understand the effect of material parameters on ΔKth.

Determination of Gradient-Elastic Constants in Cubic Solids

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1235-1239 ◽  
Author(s):  
H. J. Hackeloer ◽  
O. Kanert
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Point Defects ◽  
Elastic Constants ◽  
Lattice Distortion ◽  
Elastic Stress ◽  
Order Of Magnitude ◽  
The Given

Abstract The effect of static elastic stress on the NMR signal in LiCl35 , Rb85Cl35 , and Rb87Br is used to determine the gradient elastic constants relating the electric field gradient at the given nucleus to the elastic deformation. In contrast to previous experiments the quadrupole distortion produced by internal lattice distortion (point defects, dislocations etc.) is considered. Neglecting these distortions leads to an error in the determination of the gradient elastic constants by an order of magnitude.

Modifications of plasma edge electric field and confinement properties by limiter biasing on the KT-5C tokamak

1995 ◽  
Vol 54 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Hui Gao ◽  
Kan Zhai ◽  
Yi-Zhi Wen ◽  
Shu-De Wan ◽  
Gui-Ding Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electron Temperature ◽  
Particle Flux ◽  
Plasma Potential ◽  
Edge Plasma ◽  
Plasma Edge ◽  
Confinement Time ◽  
Plasma Confinement ◽  
Particle Confinement

Experiments using a biased multiblock limiter in the KT-5C tokamak show that positive biasing is more effective than negative biasing in modifying the edge electric field, suppressing fluctuations and improving plasma confinement. The biasing effect varies with the limiter area, the toroidal magnetic field and the biasing voltage. By positive biasing, the edge profiles of the plasma potential, the electron temperature and the density become steeper, resulting in a reduced edge particle flux, an increased global particle confinement time and lower fluctuation levels of the edge plasma.

Development of a method for multielemental determination in water by EDXRF with radioisotopic source of 238Pu.

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Camilo Fuentes Serrano ◽  
Juan Reinaldo Estevez Alvares ◽  
Alfredo Montero Alvarez ◽  
Ivan Pupo Gonzales ◽  
Zahily Herrero Fernandez ◽  
...  
Keyword(s):  
Thin Layer ◽  
Expanded Uncertainty ◽  
Considerable Decrease ◽  
X Ray ◽  
Precipitation Efficiency ◽  
Method Of Determination ◽  
Sensitivity Curves ◽  
Order Of Magnitude ◽  
Metrological Parameters

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).

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