Theoretical basal Ca II fluxes for late-type stars: results from magnetic wave models with time-dependent ionization and multi-level radiation treatments

2018 ◽  
Vol 363 (3) ◽  
Author(s):  
Diaa E. Fawzy ◽  
K. Stȩpień
Keyword(s):  
Time Dependent ◽  
Late Type ◽  
Magnetic Wave ◽  
Multi Level ◽  
Wave Models ◽  
Radiation Treatments

scholarly journals Time-dependent shot noise in multi-level quantum dot-based single-electron devices

2015 ◽  
Vol 30 (5) ◽  
pp. 055002 ◽  
Author(s):  
V Talbo ◽  
J Mateos ◽  
S Retailleau ◽  
P Dollfus ◽  
T González
Keyword(s):  
Quantum Dot ◽  
Shot Noise ◽  
Time Dependent ◽  
Single Electron ◽  
Multi Level ◽  
Single Electron Devices ◽  
Electron Devices

Dynamics and Heating of Chromospheres

2004 ◽  
Vol 219 ◽  
pp. 115-122 ◽  
Author(s):  
Wolfgang Kalkofen
Keyword(s):  
Temperature Profile ◽  
Acoustic Waves ◽  
Large Amplitude ◽  
Time Dependent ◽  
Temperature Structure ◽  
The Sun ◽  
Late Type ◽  
Spherical Waves ◽  
Spatial And Temporal Characteristics ◽  
Chromospheric Heating

Heating and dynamics of the solar as well as stellar chromospheres are separate phenomena, judging by their spatial and temporal characteristics in the Sun. Simulations of chromospheric heating in late-type stars as well as simulations of the dynamics of the large-amplitude oscillations of internetwork calcium bright points in the solar atmosphere reproduce the main features of the respective phenomena. Differences between models and observations imply (1) that the Sun has a permanent, hot chromosphere and that its temperature structure cannot be obtained by averaging the time-dependent temperature profile of a model that describes only the oscillations, and (2) that the acoustic waves causing the dynamics and the heating propagate upward as spherical waves.

scholarly journals D5.4 Report on MLMC for time dependent problems

2021 ◽  
Author(s):  
Q. Ayoul-Guilmard ◽  
S. Ganesh ◽  
M. Nuñez ◽  
R. Tosi ◽  
F. Nobile ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Time Window ◽  
Practical Interest ◽  
Time Dependent ◽  
Flow Problems ◽  
Control Variate ◽  
Multi Level ◽  
High Reynolds ◽  
Time Dependent Problems ◽  
Different Levels

In this report, we study the use of Multi-Level Monte Carlo (MLMC) methods for time dependent problems. It was found that the usability of MLMC methods depends strongly on whether or not the underlying time dependent problem is chaotic in nature. Numerical experiments are conducted on both simple problems, as well as fluid flow problems of practical interest to the ExaQUte project, to demonstrate this. For the non-chaotic cases, the hypotheses that enable the use of MLMC methods were found to be satisfied. For the chaotic cases, especially the case of high Reynolds’ number fluid flow, the hypotheses were not satisfied. However, it was found that correlations between the different levels were high enough to merit the use of multi-fidelity or control-variate approaches. It was also noted that MLMC methods could work for chaotic problems if the time window of analysis were chosen to be small enough. Future studies are proposed to examine this possibility.

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