Global well-posedness and time-decay for the full compressible non-resistive MHD equations in a 3D infinite slab

This paper is concerned with the global well-posedness and time-decay of the system of full compressible viscous non-resistive MHD fluids in a three-dimensional horizontally infinite slab with finite height. We reformulate our analysis to Lagrangian coordinates, and then develop a new mathematical approach to establish global well-posedness of the MHD system, which requires no compatibility conditions on the initial data.     

Quantitative uniqueness estimates for the general second order elliptic equations

In this paper we study quantitative uniqueness estimates of solutions to general second order elliptic equations with magnetic and electric potentials. We derive lower bounds of decay rate at infinity for any nontrivial solution under some general assumptions. The lower bounds depend on asymptotic behaviors of magnetic and electric potentials. The proof is carried out by the Carleman method and bootstrapping arguments.     

Global solution to the n-dimensional non-resistive MHD system with damping in magnetic field

The global existence is obtained for the solution to the viscous non-resistive MHD system with magnetic damping in ${\mathbb{R}}^n(n\ge 2)$. This study is inspired by the recent examinations obtained by Fefferman et al. (2014) and Chemin et al. (2016) on the local well-posedness of the viscous non-resistive MHD system.     

Global existence and decay of smooth solution for the 2-D MHD equations without magnetic diffusion

We prove the global existence and the decay estimates of small smooth solution for the 2-D MHD equations without magnetic diffusion. This confirms the numerical observation that the energy of the MHD equations is dissipated at a rate independent of the ohmic resistivity.     

Sharp estimates for pseudo-differential operators with symbols of limited smoothness and commutators

We consider here pseudo-differential operators whose symbol σ(x,ξ) is not infinitely smooth with respect to x. Decomposing such symbols into four—sometimes five—components and using tools of paradifferential calculus, we derive sharp estimates on the action of such pseudo-differential operators on Sobolev spaces and give explicit expressions for their operator norm in terms of the symbol σ(x,ξ). We also study commutator estimates involving such operators, and generalize or improve the so-called Kato-Ponce and Calderon-Coifman-Meyer estimates in various ways.     

Decoupled schemes for unsteady MHD equations. I. time discretization

In this article, a time discretization decoupled scheme for two‐dimensional magnetohydrodynamics equations is proposed. The almost unconditional stability and convergence of this scheme are provided. The optimal error estimates for velocity and magnet are provided, and the optimal error estimate for pressure are deduced as well. Finite element spatial discretization and numerical implementation are considered in our article (Zhang and He, Comput Math Appl 69 (2015), 1390–1406). © 2017 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 33: 956–973, 2017     

Regularity criteria for the three-dimensional MHD equations

In this paper,we consider regularity criteria for solutions to the 3D MHD equations with incompressible conditions.By using some classical inequalities,we obtain the regularity of strong solutions to the three-dimensional MHD equations under certain sufficient conditions in terms of one component of the velocity field and the magnetic field respectively.     

A Liouville-type theorem for the stationary MHD equations

We establish a new Liouville-type theorem for solutions of the stationary MHD equations imposing asymmetric oscillation growth conditions on the tensor-valued functions for the velocity and the magnetic field.     

Boundedness for the commutator of convolution operator

A boundedness result is established for sublinear operators on homogeneous Herz spaces. As applications, a new result about the weighted boundedness of commutators of convolution operators is obtained.     

Energy dissipation for weak solutions of incompressible MHD equations

In this article, we mainly study the local equation of energy for weak solutions of 3D MHD equations. We define a dissipation term D(u, B) that stems from an eventual lack of smoothness in the solution, and then obtain a local equation of energy for weak solutions of 3D MHD equations. Finally, we consider the 2D case at the end of this article.     

On the uniqueness for the 2D MHD equations without magnetic diffusion

In this paper, we obtain the uniqueness of the 2D MHD equations, which fills the gap of recent work by Chemin et al. (2015).     

Existence of solutions for the MHD-Leray-alpha equations and their relations to the MHD equations

In this paper we derive some new equations and we call them MHD-Leray-alpha equations which are similar to the MHD equations. We put forward the concept of weak and strong solutions for the new equations. Whether the 3-dimensional MHD equations have a unique weak solution is unknown, however, there is a unique weak solution for the 3-dimensional MHD-Leray-alpha equations. The global existence of strong solution and the Gevrey class regularity for the new equations are also obtained. Furthermore, we prove that the solutions of the MHD-Leray-alpha equations converge to the solution of the MHD equations in the weak sense as the parameter ε in the new equations converges to zero.     

Dini estimates for nonlocal fully nonlinear elliptic equations

We obtain Dini type estimates for a class of concave fully nonlinear nonlocal elliptic equations of order $\sigma \in (0,2)$ with rough and non-symmetric kernels. The proof is based on a novel application of Campanato's approach and a refined $C^{\sigma +\alpha }$ estimate in [9].     

Solvability of an inhomogeneous boundary value problem for steady MHD equations

In this paper, we consider the steady MHD equations with inhomogeneous boundary conditions for the velocity and the tangential component of the magnetic field. Using a new construction of the magnetic lifting, we obtain existence of weak solutions under sharp assumption on boundary data for the magnetic field.     

Global existence and zero α limit of the 3D incompressible two‐fluid MHD equations

In this paper, we establish global existence of strong solutions to the 3D incompressible two‐fluid MHD equations with small initial data. In addition, the explicit convergence rate of strong solutions from the two‐fluid MHD equations to the Hall‐MHD equations is obtained as . Copyright © 2017 John Wiley & Sons, Ltd.     

Asymmetric and moving-frame approaches to MHD equations

The magnetohydrodynamic (MHD) equations of incompressible viscous fluids with finite electrical conductivity describe the motion of viscous electrically conducting fluids in a magnetic field. In this paper, we find eight families of solutions of these equations by Xu’s asymmetric and moving frame methods. A family of singular solutions may reflect basic characteristics of vortices. The other solutions are globally analytic with respect to the spacial variables. Our solutions may help engineers to develop more effective algorithms to find physical numeric solutions to practical models.     

On regularity criteria in terms of pressure for the 3D viscous MHD equations

In this article, we consider regularity of solutions to the 3D viscous MHD equations. Regularity criteria are established in terms of the pressure or the gradient of pressure, which improve the results in Y. Zhou [Regularity criteria for the 3D MHD equations in terms of the pressure, Int. J. Non-Linear Mech. 41(10) (2006), pp. 1174–1180] where additional conditions on the magnetic field are also needed.