A comparative measurement of the neutral density and particle confinement time in EBT-S

1986 ◽  
Vol 35 (3) ◽  
pp. 519-528 ◽  
Author(s):  
John C. Glowienka ◽  
Roger K. Richards
Keyword(s):  
Measurement Techniques ◽  
Spectroscopic Measurement ◽  
Neutral Density ◽  
Confinement Time ◽  
Comparative Measurement ◽  
Decay Measurement ◽  
Electron Density And Temperature ◽  
Scale Experiment ◽  
Fast Ion ◽  
Particle Confinement

The neutral density and particle confinement time in the ELMO Bumpy Torus-Scale Experiment (EBT-S) have been determined by two different techniques. These involve a spectroscopic measurement of molecular and atomic hydrogen emissions and a time-decay measurement of a fast-ion population using a diagnostic neutral beam. The results from both diagnostics exhibit identical trends for either estimate, although the absolute values differ by a factor of 2 to 3. The observed variations with fill gas pressure and microwave power from either technique are consistent with measurements of electron density and temperature. In this paper, the measurement techniques are discussed, and the results are compared in the context of consistency with independently observed plasma behaviour.

Theoretical calculation of electron density and temperature in the edge of tokamak

2017 ◽  
Vol 31 (17) ◽  
pp. 1750196 ◽  
Author(s):  
Muhammad Asif ◽  
Anila Asif
Keyword(s):  
Theoretical Calculation ◽  
Electron Density ◽  
Langmuir Probe ◽  
Temporal Evolution ◽  
Edge Plasma ◽  
Confinement Time ◽  
Electron Density And Temperature ◽  
Particle Confinement ◽  
Good Agreement ◽  
Probe Array

In this work, we use a method based on the concept of particle confinement time [Formula: see text] uniqueness to calculate the electron density and temperature in ohmically heated, edge plasma of the Hefei tokamak-7. Here, with the help of the data taken from Johnson and Hinnov’s table, we have done an extensive work to find electron densities and temperatures that satisfy the [Formula: see text] uniqueness to evaluate the temporal evolution of electron density [Formula: see text] and temperature [Formula: see text]. The results are in good agreement as measured from the Langmuir probe array in previous works.

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.

Placement of a fast ion loss detector array for neutral beam injected particles in Wendelstein 7-X

2021 ◽  
Author(s):  
David Kulla ◽  
Samuel A Lazerson ◽  
Sibylle Günter ◽  
Matthias Hirsch ◽  
Dirk Hartmann ◽  
...  
Keyword(s):  
Neutral Beam ◽  
Injection System ◽  
Faraday Cup ◽  
Experimental Parameters ◽  
Detector Output ◽  
Wall Collision ◽  
The Individual ◽  
Fast Ion ◽  
Particle Confinement ◽  
Individual Detector

Abstract In light of measuring the fast ionized particle confinement in the stellarator Wendelstein 7-X, particles generated by the neutral beam injection system are simulated to determine the placement of an array of faraday-cup fast ion loss detectors. This array is important due to the localization of the loss pattern, which changes drastically with experimental parameters. The Monte Carlo codes BEAMS3D and ASCOT5 are used for the simulations, following the particles from injection to wall collision. Different magnetic configurations and plasma pressures are investigated in this manner, and a configuration suitable for measuring the loss fraction is found. It qualitatively reproduces the global losses, is installable in locations of current carbon wall-tiles and the individual detector output appears well-suited for experimental purposes.

scholarly journals Response of impurity particle confinement time to external actuators in QH-mode plasmas on DIII-D

2014 ◽  
Vol 54 (11) ◽  
pp. 114011 ◽  
Author(s):  
B.A. Grierson ◽  
K.H. Burrell ◽  
A.M. Garofalo ◽  
W.M. Solomon ◽  
A. Diallo ◽  
...  
Keyword(s):  
Confinement Time ◽  
Impurity Particle ◽  
Particle Confinement
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