A 170 GHz time-dependent multi-mode coaxial gyrotron with inner corrugation

2017 ◽  
Vol 24 (4) ◽  
pp. 043108 ◽  
Author(s):  
Shenyong Hou ◽  
Chongcong Hou ◽  
Sheng Yu ◽  
Hongfu Li
Keyword(s):  
Time Dependent ◽  
Coaxial Gyrotron ◽  
Multi Mode

Prediction of the FOM FEM experimental results using multi-mode time-dependent simulations

1998 ◽  
pp. 45-49
Author(s):  
M. Caplan ◽  
W.A. Bongers ◽  
M. Valentini ◽  
W.H. Urbanus ◽  
A.G.A. Verhoeven ◽  
...  
Keyword(s):  
Experimental Results ◽  
Time Dependent ◽  
Multi Mode

Exact solution for a time-dependent multi-mode coupled quadratic Bose system

2010 ◽  
Vol 43 (45) ◽  
pp. 455211
Author(s):  
Xiu-Wei Xu ◽  
Hai-Feng Mu ◽  
Shu-Yan Liu ◽  
Chun Guo
Keyword(s):  
Exact Solution ◽  
Time Dependent ◽  
Bose System ◽  
Multi Mode

scholarly journals Multi-mode excitation drives disorder during the ultrafast melting of a C4-symmetry-broken phase

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Daniel Perez-Salinas ◽  
Allan S. Johnson ◽  
Dharmalingam Prabhakaran ◽  
Simon Wall
Keyword(s):  
Phase Transitions ◽  
Order Parameter ◽  
Landau Theory ◽  
Mean Field ◽  
Atomic Scale ◽  
Time Dependent ◽  
Ginzburg Landau ◽  
Mode Excitation ◽  
The Mean ◽  
Multi Mode

AbstractSpontaneous C4-symmetry breaking phases are ubiquitous in layered quantum materials, and often compete with other phases such as superconductivity. Preferential suppression of the symmetry broken phases by light has been used to explain non-equilibrium light induced superconductivity, metallicity, and the creation of metastable states. Key to understanding how these phases emerge is understanding how C4 symmetry is restored. A leading approach is based on time-dependent Ginzburg-Landau theory, which explains the coherence response seen in many systems. However, we show that, for the case of the single layered manganite La0.5Sr1.5MnO4, the theory fails. Instead, we find an ultrafast inhomogeneous disordering transition in which the mean-field order parameter no longer reflects the atomic-scale state of the system. Our results suggest that disorder may be common to light-induced phase transitions, and methods beyond the mean-field are necessary for understanding and manipulating photoinduced phases.

scholarly journals Compact MDDs for Pseudo-Boolean Constraints with At-Most-One Relations in Resource-Constrained Scheduling Problems

2017 ◽  
Author(s):  
Miquel Bofill ◽  
Jordi Coll ◽  
Josep Suy ◽  
Mateu Villaret
Keyword(s):  
Project Scheduling ◽  
Resource Constraints ◽  
Time Dependent ◽  
Scheduling Problems ◽  
Resource Constrained ◽  
Binary Decision ◽  
Compact Binary ◽  
Order Of Magnitude ◽  
Project Scheduling Problem ◽  
Multi Mode

Pseudo-Boolean (PB) constraints are usually encoded into Boolean clauses using compact Binary Decision Diagram (BDD) representations. Although these constraints appear in many problems, they are particularly useful for representing resource constraints in scheduling problems. Sometimes, the Boolean variables in the PB constraints have implicit at-most-one relations. In this work we introduce a way to take advantage of these implicit relations to obtain a compact Multi-Decision Diagram (MDD) representation for those PB constraints. We provide empirical evidence of the usefulness of this technique for some Resource-Constrained Project Scheduling Problem (RCPSP) variants, namely the Multi-Mode RCPSP (MRCPSP) and the RCPSP with Time-Dependent Resource Capacities and Requests (RCPSP/t). The size reduction of the representation of the PB constraints lets us decrease the number of Boolean variables in the encodings by one order of magnitude. We close/certify the optimum of many instances of these problems.

The transition to turbulence in shock-driven mixing: effects of Mach number and initial conditions

2019 ◽  
Vol 871 ◽  
pp. 595-635 ◽  
Author(s):  
Mohammad Mohaghar ◽  
John Carter ◽  
Gokul Pathikonda ◽  
Devesh Ranjan
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Large Scale ◽  
Initial Conditions ◽  
Incident Shock ◽  
Time Dependent ◽  
High Mach Number ◽  
High Mach ◽  
Number Case ◽  
Multi Mode

The effects of incident shock strength on the mixing transition in the Richtmyer–Meshkov instability (RMI) are experimentally investigated using simultaneous density–velocity measurements. This effort uses a shock with an incident Mach number of 1.9, in concert with previous work at Mach 1.55 (Mohaghar et al., J. Fluid Mech., vol. 831, 2017 pp. 779–825) where each case is followed by a reshock wave. Single- and multi-mode interfaces are used to quantify the effect of initial conditions on the evolution of the RMI. The interface between light and heavy gases ($\text{N}_{2}/\text{CO}_{2}$, Atwood number, $A\approx 0.22$; amplitude to wavelength ratio of 0.088) is created in an inclined shock tube at $80^{\circ }$ relative to the horizontal, resulting in a predominantly single-mode perturbation. To investigate the effects of initial perturbations on the mixing transition, a multi-mode inclined interface is also created via shear and buoyancy superposed on the dominant inclined perturbation. The evolution of mixing is investigated via the density fields by computing mixed mass and mixed-mass thickness, along with mixing width, mixedness and the density self-correlation (DSC). It is shown that the amount of mixing is dependent on both initial conditions and incident shock Mach number. Evolution of the density self-correlation is discussed and the relative importance of different DSC terms is shown through fields and spanwise-averaged profiles. The localized distribution of vorticity and the development of roll-up features in the flow are studied through the evolution of interface wrinkling and length of the interface edge, which indicate that the vorticity concentration shows a strong dependence on the Mach number. The contribution of different terms in the Favre-averaged Reynolds stress is shown, and while the mean density-velocity fluctuation correlation term, $\langle \unicode[STIX]{x1D70C}\rangle \langle u_{i}^{\prime }u_{j}^{\prime }\rangle$, is dominant, a high dependency on the initial condition and reshock is observed for the turbulent mass-flux term. Mixing transition is analysed through two criteria: the Reynolds number (Dimotakis, J. Fluid Mech., vol. 409, 2000, pp. 69–98) for mixing transition and Zhou (Phys. Plasmas, vol. 14 (8), 2007, 082701 for minimum state) and the time-dependent length scales (Robey et al., Phys. Plasmas, vol. 10 (3), 2003, 614622; Zhou et al., Phys. Rev. E, vol. 67 (5), 2003, 056305). The Reynolds number threshold is surpassed in all cases after reshock. In addition, the Reynolds number is around the threshold range for the multi-mode, high Mach number case ($M\sim 1.9$) before reshock. However, the time-dependent length-scale threshold is surpassed by all cases only at the latest time after reshock, while all cases at early times after reshock and the high Mach number case at the latest time before reshock fall around the threshold. The scaling analysis of the turbulent kinetic energy spectra after reshock at the latest time, at which mixing transition analysis suggests that an inertial range has formed, indicates power scaling of $-1.8\pm 0.05$ for the low Mach number case and $-2.1\pm 0.1$ for the higher Mach number case. This could possibly be related to the high anisotropy observed in this flow resulting from strong, large-scale streamwise fluctuations produced by large-scale shear.

Multi-Mode Study of Time-Dependent Thermal Convection With Hexagonal Planforms

1984 ◽  
Vol 5 (4) ◽  
pp. 483-487 ◽  
Author(s):  
J. M. Lopez ◽  
J. O. Murphy
Keyword(s):  
Magnetic Fields ◽  
Time Dependence ◽  
Thermal Convection ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Time Dependent ◽  
Flexible Approach ◽  
Large Density ◽  
Non Linear ◽  
Multi Mode

Truncated modal expansions have provided a powerful, reasonably accurate and flexible approach to the problem of non-linear thermal convection. They permit tractable numerical solutions of three-dimensional cellular motions, as well as readily accommodating large density variations, time dependence, rotation and magnetic fields.

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