Inverse Problem in the Kuramoto Model with a Phase Lag: Application to the Sun

2020 ◽  
Vol 30 (12) ◽  
pp. 2050165
Author(s):  
Elena Blanter ◽  
Mikhail Shnirman
Keyword(s):  
Inverse Problem ◽  
Meridional Circulation ◽  
Phase Locking ◽  
Radial Profile ◽  
Kuramoto Model ◽  
Problem Solution ◽  
Phase Lag ◽  
The Sun ◽  
The Kuramoto Model

We solve the inverse problem in the Kuramoto model with three nonidentical oscillators and a phase lag. The model represents a three-cell-in-depth radial profile of the solar meridional circulation in each solar hemisphere and describes the synchronization between the two components (toroidal and poloidal) of the solar magnetic field. We reconstruct natural frequencies of the top and the bottom oscillators from the evolution of their phases when the oscillators are phase-locked. The phase-locking allows to solve the inverse problem when the phase of the middle oscillator is not available. We present the exact solution and investigate its stability. The model reveals a crucial role of the phase lag in the inverse problem solution. We apply the model to the reconstruction of the deep meridional circulation of the Sun and discuss peculiarities of its evolution in terms of solar dynamo.

Volume Bounds for the Phase-Locking Region in the Kuramoto Model

2018 ◽  
Vol 17 (1) ◽  
pp. 128-156 ◽  
Author(s):  
Jared C. Bronski ◽  
Timothy Ferguson
Keyword(s):  
Phase Locking ◽  
Kuramoto Model ◽  
The Kuramoto Model

The role of science in the study of and response to space threats

2019 ◽  
Vol 89 (8) ◽  
pp. 777-799
Author(s):  
B. M. Shustov
Keyword(s):  
Comparative Analysis ◽  
20Th Century ◽  
21St Century ◽  
Space Debris ◽  
The Sun ◽  
National Program ◽  
Biological Hazard ◽  
Academy Of Sciences ◽  
Space Activities

During the second half of the 20th century and the beginning of the 21st century, space hazards multiplied, the most urgent of which is space debris. Professionals working in space are exposed to this hazard daily and are aware of it as a problem. Furthermore, increasing attention is being paid to the unpredictable behavior of the Sun, which produces the so-called space weather. The asteroid-comet hazard is considered as potentially having the most catastrophic consequences. No manifestations of biological hazard have yet been observed, although as space activities develop, it is becoming increasingly important. The appropriate time scale for astrophysical hazards is many millions of years, so from a practical perspective, they have no importance. This article briefly describes the main types of space hazards. The author analyzes the results of research and practical work in the field, both worldwide and specifically in Russia. Comparative analysis leads to the clear conclusion that a national program must be developed for the study of space hazards and to respond to space threats. This article is based on a report made by the author at the meeting of the Presidium of the Russian Academy of Sciences (RAS) on January 15, 2019.

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