English

Lie Symmetries for the Shallow Water Magnetohydrodynamics Equations in a Rotating Reference Frame

Mathematical Physics 2024-12-20 v1 Analysis of PDEs math.MP Plasma Physics

Abstract

We perform a detailed Lie symmetry analysis for the hyperbolic system of partial differential equations that describe the one-dimensional Shallow Water magnetohydrodynamics equations within a rotating reference frame. We consider a relaxing condition (hB)0\mathbf{\mathbf{\nabla }}\left( h\mathbf{B} \right) \neq 0 for the one-dimensional problem, which has been used to overcome unphysical behaviors. The hyperbolic system of partial differential equations depends on two parameters: the constant gravitational potential gg and the Coriolis term f0f_{0}, related to the constant rotation of the reference frame. For four different cases, namely g=0, f0=0g=0,~f_{0}=0; g0, f0=0g\neq 0\,,~f_{0}=0; g=0g=0, f00f_{0}\neq 0; and g0g\neq 0, f00f_{0}\neq 0 the admitted Lie symmetries for the hyperbolic system form different Lie algebras. Specifically the admitted Lie algebras are the L10={A3,3A2,1}sA5,34aL^{10}=\left\{ A_{3,3}\rtimes A_{2,1}\right\} \otimes _{s}A_{5,34}^{a}; % L^{8}=A_{2,1}\rtimes A_{6,22}; L7=A3,5{A2,1A2,1}L^{7}=A_{3,5}\rtimes\left\{ A_{2,1}\rtimes A_{2,1}\right\} ; and L6=A3,5A3,3 L^{6}=A_{3,5}\rtimes A_{3,3}~respectively, where we use the Morozov-Mubarakzyanov-Patera classification scheme. For the general case where f0g0f_{0}g\neq 0, we derive all the invariants for the Adjoint action of the Lie algebra L6L^{6} and its subalgebras, and we calculate all the elements of the one-dimensional optimal system. These elements are then considered to define similarity transformations and construct analytic solutions for the hyperbolic system.

Keywords

Cite

@article{arxiv.2412.14578,
  title  = {Lie Symmetries for the Shallow Water Magnetohydrodynamics Equations in a Rotating Reference Frame},
  author = {Andronikos Paliathanasis and Amlan Halder},
  journal= {arXiv preprint arXiv:2412.14578},
  year   = {2024}
}

Comments

32 pages, 3 figures