Well-posedness for Ohkitani model and long-time existence for surface quasi-geostrophic equations

Fuente: arXiv
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Main Authors: Chae, Dongho, Jeong, In-Jee, Na, Jungkyoung, Oh, Sung-Jin
Format: Preprint
Published: 2023
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author Chae, Dongho
Jeong, In-Jee
Na, Jungkyoung
Oh, Sung-Jin
author_facet Chae, Dongho
Jeong, In-Jee
Na, Jungkyoung
Oh, Sung-Jin
contents We consider the Cauchy problem for the logarithmically singular surface quasi-geostrophic (SQG) equation, introduced by Ohkitani, $$\partial_t θ- \nabla^\perp \log(10+(-Δ)^{\frac12})θ\cdot \nabla θ= 0 ,$$ and establish local existence and uniqueness of smooth solutions in the scale of Sobolev spaces with exponent decreasing with time. Such a decrease of the Sobolev exponent is necessary, as we have shown in the companion paper that the problem is strongly ill-posed in any fixed Sobolev spaces. The time dependence of the Sobolev exponent can be removed when there is a dissipation term strictly stronger than log. These results improve wellposedness statements by Chae, Constantin, Córdoba, Gancedo, and Wu in \cite{CCCGW}. This well-posedness result can be applied to describe the long-time dynamics of the $δ$-SQG equations, defined by $$\partial_t θ+ \nabla^\perp (10+(-Δ)^{\frac12})^{-δ}θ\cdot \nabla θ= 0,$$ for all sufficiently small $δ>0$ depending on the size of the initial data. For the same range of $δ$, we establish global well-posedness of smooth solutions to the logarithmically dissipative counterpart: $$\partial_t θ+ \nabla^\perp (10+(-Δ)^{\frac12})^{-δ}θ\cdot \nabla θ+ \log(10+(-Δ)^{\frac12})θ= 0.$$
format Preprint
id arxiv_https___arxiv_org_abs_2308_02107
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Well-posedness for Ohkitani model and long-time existence for surface quasi-geostrophic equations
Chae, Dongho
Jeong, In-Jee
Na, Jungkyoung
Oh, Sung-Jin
Analysis of PDEs
Mathematical Physics
We consider the Cauchy problem for the logarithmically singular surface quasi-geostrophic (SQG) equation, introduced by Ohkitani, $$\partial_t θ- \nabla^\perp \log(10+(-Δ)^{\frac12})θ\cdot \nabla θ= 0 ,$$ and establish local existence and uniqueness of smooth solutions in the scale of Sobolev spaces with exponent decreasing with time. Such a decrease of the Sobolev exponent is necessary, as we have shown in the companion paper that the problem is strongly ill-posed in any fixed Sobolev spaces. The time dependence of the Sobolev exponent can be removed when there is a dissipation term strictly stronger than log. These results improve wellposedness statements by Chae, Constantin, Córdoba, Gancedo, and Wu in \cite{CCCGW}. This well-posedness result can be applied to describe the long-time dynamics of the $δ$-SQG equations, defined by $$\partial_t θ+ \nabla^\perp (10+(-Δ)^{\frac12})^{-δ}θ\cdot \nabla θ= 0,$$ for all sufficiently small $δ>0$ depending on the size of the initial data. For the same range of $δ$, we establish global well-posedness of smooth solutions to the logarithmically dissipative counterpart: $$\partial_t θ+ \nabla^\perp (10+(-Δ)^{\frac12})^{-δ}θ\cdot \nabla θ+ \log(10+(-Δ)^{\frac12})θ= 0.$$
title Well-posedness for Ohkitani model and long-time existence for surface quasi-geostrophic equations
topic Analysis of PDEs
Mathematical Physics
url https://arxiv.org/abs/2308.02107