Effect of L-H and H-L Transitions on Tokamak-reactor Operation
Yury Gott,
Eduard Yurchenko
Issue:
Volume 9, Issue 1, January 2020
Pages:
1-6
Received:
17 December 2019
Accepted:
31 December 2019
Published:
17 January 2020
Abstract: The effect of L-H and H-L transitions on the tokamak-reactor operation is considered. Both initial modes are considered as quasi-equilibrium states with the same thermal energy for constant total toroidal currents. A method has been developed for quantification the change in neutron yield in a tokamak- reactor during these transitions occurring over times much shorter than the plasma energy confinement time. The method is based on the use of duality of solutions of the Grad-Shafranov equation. The arbitrary functions included in this equation were found as a result of approximation of the normalized plasma pressure profiles, presented versus on the radial flow coordinate obtained at the DIII-D facility. To calculate changes in neutron fluxes during L-H and back H-L transitions, we used these plasma pressure distributions for the ITER device parameters presented in Cartesian coordinates. A numerical calculation showed that in the back H-L transition, a large spike on the global neutron production is possible, which was previously discovered experimentally (ALCATOR-C-Mode, 2001). Since such an increase in neutron fluxes during tokamak-reactor ITER operation poses a serious threat to both the personnel and the facility itself, it is necessary to exclude the possibility of such transitions. Thus, it is necessary to develop such a reactor design that would make it possible to obtain a self-sustaining thermonuclear reaction in the L-mode operation.
Abstract: The effect of L-H and H-L transitions on the tokamak-reactor operation is considered. Both initial modes are considered as quasi-equilibrium states with the same thermal energy for constant total toroidal currents. A method has been developed for quantification the change in neutron yield in a tokamak- reactor during these transitions occurring ove...
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Nonequilibrium Spin-Hall Detector with Alternating Current
Yurii Nikolaevich Chiang,
Mikhail Olegovich Dzyuba
Issue:
Volume 9, Issue 1, January 2020
Pages:
7-10
Received:
15 April 2020
Accepted:
11 May 2020
Published:
27 May 2020
Abstract: An oscillographic study of the Hall voltage with an unpolarized alternating current through a platinum sample revealed chiral features of the Hall effect, which clearly demonstrate the presence of the spin Hall effect in metals with a noticeable spin-orbit interaction. It was confirmed that, as in the case of direct current, the possibility of a spin-Hall effect is associated with the presence of an imbalance of the spins and charges at the edges of the samples, which is realized using their asymmetric geometry. In particular, it was found that such chiral features of the nonequilibrium spin-Hall effect (NSHE), such as independence from the direction of the injection current and the direction of the constant magnetic field, in the case of alternating current, make it possible to obtain a double-frequency transverse voltage, which can be used as a platform for creating spintronics devices.
Abstract: An oscillographic study of the Hall voltage with an unpolarized alternating current through a platinum sample revealed chiral features of the Hall effect, which clearly demonstrate the presence of the spin Hall effect in metals with a noticeable spin-orbit interaction. It was confirmed that, as in the case of direct current, the possibility of a sp...
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