Measurements of large poloidal variations of impurity density in the Alcator C-Mod H-mode barrier region

2002 ◽  
Vol 9 (10) ◽  
pp. 4188-4192 ◽  
Author(s):  
T. Sunn Pedersen ◽  
R. S. Granetz ◽  
E. S. Marmar ◽  
D. Mossessian ◽  
J. W. Hughes ◽  
...  
Keyword(s):  
Impurity Density ◽  
Barrier Region

Ionized impurity density and mobility in n-GaAs

1971 ◽  
Vol 8 (2) ◽  
pp. K89-K92 ◽  
Author(s):  
D. Kranzer ◽  
G. Eberharter
Keyword(s):  
Impurity Density

X‐ray tomography of hot electrons in the barrier region of the tandem mirror GAMMA 10

1990 ◽  
Vol 67 (4) ◽  
pp. 1694-1699 ◽  
Author(s):  
T. Kondoh ◽  
T. Cho ◽  
M. Hirata ◽  
N. Yamaguchi ◽  
T. Saito ◽  
...  
Keyword(s):  
Hot Electrons ◽  
X Ray ◽  
Tandem Mirror ◽  
Barrier Region

scholarly journals Perfect valley filter in strained graphene with single barrier region

AIP Advances ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 056303 ◽  
Author(s):  
Can Yesilyurt ◽  
Seng Ghee Tan ◽  
Gengchiau Liang ◽  
Mansoor B. A. Jalil
Keyword(s):  
Barrier Region ◽  
Strained Graphene

scholarly journals Radiated energy and impurity density changes during intensive hydrogen influx in the PLT tokamak

1981 ◽  
Author(s):  
E. Hinnov ◽  
J. Hosea ◽  
H. Hsuan ◽  
F. Jobes ◽  
E. Meservey ◽  
...  
Keyword(s):  
Impurity Density ◽  
Radiated Energy

Non-Equilibrium Green’s Function Modeling of the Transport Characteristics of Magnetic Tunnel Junctions Containing Anderson Impurities

SPIN ◽  
2020 ◽  
Vol 10 (01) ◽  
pp. 2050006
Author(s):  
Parvathy Harikumar ◽  
S. Mathi Jaya
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Many Body ◽  
Applied Bias ◽  
Tunnel Current ◽  
Spin Polarized ◽  
Barrier Region ◽  
Non Equilibrium Green’S Function

A nonequilibrium Green’s function (NEGF) formulation to study the transport characteristics of magnetic tunnel junctions (MTJs) that contains impurities at the barrier region and many-body interaction at the electrode region is presented. The formulation makes use of the already developed NEGF method for MTJs without any impurities and the impurity Green’s function is obtained using Haldane’s approach that explicitly takes into account the on-site Coulomb interaction ([Formula: see text]) of the impurity. The formulation is used to obtain the spin-dependent tunnel current of model MTJs as a function of the applied bias for different values of [Formula: see text] corresponding to both the parallel and antiparallel configuration of the end electrodes of the MTJ. The tunnel currents are used to obtain the tunnel magnetoresistance (TMR) of the MTJ and we observed from our study that the TMR is strongly influenced by the impurities. The TMR is found to be reduced compared to that of the MTJ without impurities and the bias dependence of the TMR is found to be strongly influenced by [Formula: see text]. Our studies revealed that the MTJ can exhibit almost completely spin polarized current at certain values of [Formula: see text].

scholarly journals Bifurcation of potential vorticity gradients across the Southern Hemisphere stratospheric polar vortex

2018 ◽  
Vol 18 (11) ◽  
pp. 8065-8077 ◽  
Author(s):  
Jonathan Conway ◽  
Greg Bodeker ◽  
Chris Cameron
Keyword(s):  
Southern Hemisphere ◽  
Potential Vorticity ◽  
Polar Vortex ◽  
Trace Gas ◽  
Stratospheric Polar Vortex ◽  
Distinct Structure ◽  
Barrier Region ◽  
Westerly Winds ◽  
Antarctic Continent ◽  
The Antarctic

Abstract. The wintertime stratospheric westerly winds circling the Antarctic continent, also known as the Southern Hemisphere polar vortex, create a barrier to mixing of air between middle and high latitudes. This dynamical isolation has important consequences for export of ozone-depleted air from the Antarctic stratosphere to lower latitudes. The prevailing view of this dynamical barrier has been an annulus compromising steep gradients of potential vorticity (PV) that create a single semi-permeable barrier to mixing. Analyses presented here show that this barrier often displays a bifurcated structure where a double-walled barrier exists. The bifurcated structure manifests as enhanced gradients of PV at two distinct latitudes – usually on the inside and outside flanks of the region of highest wind speed. Metrics that quantify the bifurcated nature of the vortex have been developed and their variation in space and time has been analysed. At most isentropic levels between 395 and 850 K, bifurcation is strongest in mid-winter and decreases dramatically during spring. From August onwards a distinct structure emerges, where elevated bifurcation remains between 475 and 600 K, and a mostly single-walled barrier occurs at other levels. While bifurcation at a given level evolves from month to month, and does not always persist through a season, interannual variations in the strength of bifurcation display coherence across multiple levels in any given month. Accounting for bifurcation allows the region of reduced mixing to be better characterised. These results suggest that improved understanding of cross-vortex mixing requires consideration of the polar vortex not as a single mixing barrier but as a barrier with internal structure that is likely to manifest as more complex gradients in trace gas concentrations across the vortex barrier region.

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