scholarly journals Electric field assisted amplification of magnetic fields in tilted Dirac cone systems

2019 ◽  
Vol 100 (4) ◽  
Author(s):  
S. A. Jafari
2018 ◽  
Vol 9 ◽  
pp. 1405-1413 ◽  
Author(s):  
Álvaro Díaz-Fernández ◽  
Natalia del Valle ◽  
Francisco Domínguez-Adame

Several IV–VI semiconductor compounds made of heavy atoms, such as Pb1 −x Sn x Te, may undergo band-inversion at the L point of the Brillouin zone upon variation of their chemical composition. This inversion gives rise to topologically distinct phases, characterized by a change in a topological invariant. In the framework of the k·p theory, band-inversion can be viewed as a change of sign of the fundamental gap. A two-band model within the envelope-function approximation predicts the appearance of midgap interface states with Dirac cone dispersions in band-inverted junctions, namely, when the gap changes sign along the growth direction. We present a thorough study of these interface electron states in the presence of crossed electric and magnetic fields, the electric field being applied along the growth direction of a band-inverted junction. We show that the Dirac cone is robust and persists even if the fields are strong. In addition, we point out that Landau levels of electron states lying in the semiconductor bands can be tailored by the electric field. Tunable devices are thus likely to be realizable, exploiting the properties studied herein.


Author(s):  
Eduardo Lascas Neto ◽  
Jonathan P Graves ◽  
Madhusudan Raghunathan ◽  
Cristian Sommariva ◽  
David Pfefferlé

Abstract Strongly peaked tungsten accumulation is a common feature of high performance plasma scenarios in JET with the ITER-like wall, particularly during MHD activity induced by m⁄n = 1⁄1 continuous modes. This study investigates the effect of 1⁄1 long living internal kink modes on heavy impurity transport in the presence of strong flows and NTV ambipolar electric field. A novel formulation which includes these effects is presented and applied in the VENUS-LEVIS code in order to follow tungsten ions in a saturated JET-like 1⁄1 internal kinked toroidally rotating plasma configuration. The synergy between 3D magnetic fields, strong flows and NTV is seen to cause tungsten accumulation in contrast to what is observed in similar axisymmetric configurations. Rapid inward transport of impurities in JET plasmas following the triggering of continuous 1⁄1 modes is explained by the work presented here, and we use the same theory to postulate why outward transport can occur in kinked ASDEX-U plasmas.


2013 ◽  
Vol 20 (3) ◽  
pp. 365-377 ◽  
Author(s):  
W. Lyatsky ◽  
M. L. Goldstein

Abstract. We present here the results of a study of interacting magnetic fields that involves a force normal to the reconnection layer. In the presence of such force, the reconnection layer becomes unstable to interchange disturbances. The interchange instability results in formation of tongues of heated plasma that leaves the reconnection layer through its wide surface rather than through its narrow ends, as is the case in traditional magnetic reconnection models. This plasma flow out of the reconnection layer facilitates the removal of plasma from the layer and leads to fast reconnection. The proposed mechanism provides fast reconnection of interacting magnetic fields and does not depend on the thickness of the reconnection layer. This instability explains the strong turbulence and bidirectional streaming of plasma that is directed toward and away from the reconnection layer that is observed frequently above reconnection layers. The force normal to the reconnection layer also accelerates the removal of plasma islands appearing in the reconnection layer during turbulent reconnection. In the presence of this force normal to the reconnection layer, these islands are removed from the reconnection layer by the "buoyancy force", as happens in the case of interchange instability that arises due to the polarization electric field generated at the boundaries of the islands.


2014 ◽  
Vol 23 (3) ◽  
pp. 037101 ◽  
Author(s):  
D. A. Rowlands ◽  
Yu-Zhong Zhang
Keyword(s):  

JOUTICA ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 255
Author(s):  
Kemal Farouq Mauladi ◽  
Nurul Fuad

Telecommunications technology is developing very rapidly, ranging from users or engineers. The development of smartphone smartphones is also increasingly in demand, so that the use of electricity needs is also increasing. The need for electricity usage has resulted in more standing voltage in some settlements. The establishment of sutet will have a negative impact on public health. In addition, the influence of electrical energy on humans occurs because the electrical energy generated by electricity generation or electricity that is channeled gives rise to electromagnetic fields. The higher the voltage required by an equipment, the greater the electric field that is distributed. Besides that, it can also find ways to reduce the negative impact of the electric and magnetic fields produced by SUTET which impacts the process of the occurrence of electric and magnetic fields on SUTET. From the problems above, the author intends to determine the effect or correlation between the impact of SUTET on cellphone network transmissions or channels. This research can later determine the negative impact caused by SUTET for the surrounding community, and the impact of SUTET radiation on cellular networks.


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