Feasibility of Superconductivity in Nonequilibrium Systems with Repulsion

Abstract

In order to improve the particle control capability of the divertor and to demonstrate the possibility of a dense and cold divertor with high confinement plasmas, a closed divertor study has been carried out on the JFT-2M tokamak. When a strong gas puff is applied into the divertor chamber, a baffling effect is revealed by enhanced radiation localization and high neutral pressure in the divertor chamber, low core fuelling and sustainment of core confinement quality. The baffling effect is further enhanced with × flow and/or current in the scrape-off layer by applying divertor biasing. A dense and cold divertor state (n div e ≈ 4 × 10 19 m −3 and T div e ≈ 4 eV), together with the improved confinement modes, can be obtained by strong gas puffing. Furthermore, the improved core confinement is not affected significantly in the high density region (ne/n G e < 0.7). The UEDA code simulation reproduces the baffling effect and a dense and cold divertor plasma with a closed divertor structure.

Topological Floquet spectrum in three dimensions via a two-photon resonance

“…It was previously studied theoretically and experimentally [34][35][36][37][38][39] , and we intend to address it in future work. According to Ref.…”

“…According to Ref. 35, coupling to phonons can yield a steady state described by a filled Floquet band with an effective temperature (on the order of the lattice temperature). Furthermore, in Ref.…”

Bistability in voltage-biased normal-metal/insulator/superconductor/insulator/normal-metal structures

“…It is a common feature of superconductors outside equilibrium. 16,17 ͒ For a symmetric coupling to the source and drain leads, one of the two states we find is superconducting ͑characterized by a nonzero order parameter͒ and the other is normal. Since we are in the regime of high tunnel barriers, at a given voltage, the superconducting island allows less current to flow between the leads than the island in the normal state.…”

“…The stability of these states strongly depend on the nature of the quasiparticle distribution function and the relaxation mechanism. 16,17,19 Proper account of superconducting fluctuations may be required to understand the transitions between the stable states and eventually to recover adiabaticity of the superconductor dynamics in the low-frequency limit. 20 In distinction from previous work, we assume that the relaxation is provided by tunneling to/from the leads rather than by inelastic processes in the bulk.…”

“…The latter forbids the use of the Boltzmann equation for the distribution function implemented in earlier studies. 16,17 Therefore our work is based on a Green's function technique.…”