Extra-wide-angle parabolic equations in motionless and moving media

2019 ◽  
Vol 145 (2) ◽  
pp. 1031-1047 ◽  
Author(s):  
Vladimir E. Ostashev ◽  
Michael B. Muhlestein ◽  
D. Keith Wilson
2021 ◽  
Author(s):  
Vladimir Ostashev ◽  
Michael Muhlestein ◽  
D. Wilson

Wide-angle parabolic equations (WAPEs) play an important role in physics. They are derived by an expansion of a square-root pseudo-differential operator in one-way wave equations, and then solved by finite-difference techniques. In the present paper, a different approach is suggested. The starting point is an extra-wide-angle parabolic equation (EWAPE) valid for small variations of the refractive index of a medium. This equation is written in an integral form, solved by a perturbation technique, and transformed to the spectral domain. The resulting split-step spectral algorithm for the EWAPE accounts for the propagation angles up to 90° with respect to the nominal direction. This EWAPE is also generalized to large variations in the refractive index. It is shown that WAPEs known in the literature are particular cases of the two EWAPEs. This provides an alternative derivation of the WAPEs, enables a better understanding of the underlying physics and ranges of their applicability, and opens an opportunity for innovative algorithms. Sound propagation in both motionless and moving media is considered. The split-step spectral algorithm is particularly useful in the latter case since complicated partial derivatives of the sound pressure and medium velocity reduce to wave vectors (essentially, propagation angles) in the spectral domain.


2020 ◽  
Vol 147 (6) ◽  
pp. 3969-3984 ◽  
Author(s):  
Vladimir E. Ostashev ◽  
D. Keith Wilson ◽  
Michael B. Muhlestein

Author(s):  
Fatima Nazare Barauna Magno ◽  
Joao Furtado de Souza ◽  
Klaus Cozzolino ◽  
Jesse Carvalho Costa ◽  
Gervasio Protasio dos Santos Cavalcante

2020 ◽  
Vol 148 (4) ◽  
pp. 2615-2615
Author(s):  
Petr V. Yuldashev ◽  
Maria M. Karzova ◽  
Vera Khokhlova ◽  
Philippe Blanc-Benon

2021 ◽  
Vol 149 (4) ◽  
pp. A93-A93
Author(s):  
Vladimir Ostashev ◽  
D. Keith Wilson

2002 ◽  
Vol 48 (6) ◽  
pp. 728 ◽  
Author(s):  
M. Yu. Trofimov

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