Approximate homotopy similarity reduction for the generalized Kawahara equation via Lie symmetry method and direct method

This paper studies the generalized Kawahara equation in terms of the approximate homotopy symmetry method and the approximate homotopy direct method. Using both methods it obtains the similarity reduction solutions and similarity reduction equations of different orders, showing that the approximate homotopy direct method yields more general approximate similarity reductions than the approximate homotopy symmetry method. The homotopy series solutions to the generalized Kawahara equation are consequently derived.

Approximate Homotopy Symmetry Reduction Method:Infinite Series Reductions to Kawahara Equation

The Kawahara equation is studied through the approximate homotopy symmetry method. Under this method we get the similarity reduction solutions of the Kawahara equation, leading to the corresponding homotopy series solutions. Furthermore, the similarity solutions of the corresponding reduced linear ordinary differential equations are also considered.

Explicit solutions to the time-fractional generalized dissipative Kawahara equation

In this paper,the generalized dissipative Kawahara equation in the sense of conformable fractional derivative is presented and solved by applying the tanh-coth-expansion and sine-cosine function techniques.The quadratic-case and cubic-case are investigated for the proposed model.Expected solutions are obtained with highlighting to the effect of the presence of the alternative fractional-derivative and the effect of the added dissipation term to the generalized Kawahara equation.Some graphical analysis is presented to support the findings of the paper.Finally,we believe that the obtained results in this work will be important and valuable in nonlinear sciences and ocean engineering.

Local and Global Existence of Solutions to Initial Value Problems of Modified Nonlinear Kawahara Equations

This paper is devoted to studying the initial value problem of the modified nonlinear Kawahara equation the first partial dervative of u to t ,the second the third ＋α the second partial dervative of u to x ,the second the third ＋β the third partial dervative of u to x ,the second the thire ＋γ the fifth partial dervative of u to x = 0,（x,t）∈R^2.We first establish several Strichartz type estimates for the fundamental solution of the corresponding linear problem. Then we apply such estimates to prove local and global existence of solutions for the initial value problem of the modified nonlinear Karahara equation. The results show that a local solution exists if the initial function uo（x） ∈ H^s（R） with s ≥ 1/4, and a global solution exists if s ≥ 2.

Global Existence of Solutions for the Cauchy Problem of the Kawahara Equation with L^2 Initial Data

In this paper we study solvability of the Cauchy problem of the Kawahara equation 偏导dtu ＋ au偏导dzu ＋ β偏导d^3xu ＋γ偏导d^5xu = 0 with L^2 initial data. By working on the Bourgain space X^r,s（R^2） associated with this equation, we prove that the Cauchy problem of the Kawahara equation is locally solvable if initial data belong to H^r（R） and -1 〈 r ≤ 0. This result combined with the energy conservation law of the Kawahara equation yields that global solutions exist if initial data belong to L^2（R）.

Global Existence of Solutions for the Kawahara Equation in Sobolev Spaces of Negative Indices

We first prove that the Cauchy problem of the Kawahara equation, δtu ＋ uδxu ＋βδx^3u＋γδx^5u = 0, is locally solvable if the initial data belong to H^r（R） and r〉 r≥-7/5, thus improving the known local well-posedness result of this equation. Next we use this local result and the method of ＂almost conservation law＂ to prove that global solutions exist if the initial data belong to H^r（R） and r〉-1/2.

Multi-Symplectic Fourier Pseudospectral Method for the Kawahara Equation

In this paper,we derive a multi-symplectic Fourier pseudospectral scheme for the Kawahara equation with special attention to the relationship between the spectral differentiation matrix and discrete Fourier transform.The relationship is crucial for implementing the scheme efficiently.By using the relationship,we can apply the Fast Fourier transform to solve the Kawahara equation.The effectiveness of the proposed methods will be demonstrated by a number of numerical examples.The numerical results also confirm that the global energy and momentum are well preserved.

Novel anlytical solution to the damped Kawahara equation and its application for modeling the dissipative nonlinear structures in a fluid medium

A novel approximate analytical solution to the linear damped Kawahara equation using a suitable hypothesis is reported for the first time.Based on the exact solutions(such as solitary waves,cnoidal waves,etc.)of the undamped Kawahara equation,the dissipative nonlinear structures like dissipative solitons and cnoidal waves are investigated.The obtained solution is considered a general solution,i.e.,it can be applied for studying the properties of all dissipative traveling waves described by the linear damped Kawahara equation.Our technique is not limited to solve the linear damped Kawahara equation only,but it can be used for solving a large number of non-integrable evolution equations related to the realistic natural phenomena.Moreover,the maximum global residual error in the whole space-time domain is estimated for checking the accuracy of the obtained solutions.The obtained solutions can help many researchers in explaining the ambiguities about the mechanisms of propagation of nonlinear waves in complex systems such as seas,oceans,plasma physics,and much more.

A numerical technique based on collocation method for solving modified Kawahara equation

In this article,a numerical solution of the modified Kawahara equation is presented by septic B-spline collocation method.Applying the von-Neumann stability analysis,the present method is shown to be unconditionally stable.L 2 and L∞error norms and conserved quantities are given at selected times.The accuracy of the proposed method is checked by test problems including motion of the single solitary wave,interaction of solitary waves and evolution of solitons.

THE CAUCHY PROBLEM OF THE MODIFIED KAWAHARA EQUATION

In this paper, we consider the local and global solutions for the modified Kawahara equation with data in the homogeneous and nonhomogeneous Besov space and the scattering result for small data. The techniques to be used are adapted from Kato＇s smoothing effect and the maximal function （in time） estimate for the free Kawahara operator e^-λt 5.

Landau quantization effects on damping Kawahara solitons in electron–positron–ion plasma in rotating ionized medium

For the dynamics of three-dimensional electron–positron–ion plasmas,a fluid quantum hydrodynamic model is proposed by considering Landau quantization effects in dense plasma.Ion–neutral collisions in the presence of the Coriolis force are also considered.The application of the reductive perturbation technique produces a wave evolution equation represented by a damped Korteweg–de Vries equation.This equation,however,is insufficient for describing waves in our system at very low dispersion coefficients.As a result,we considered the highest-order perturbation,which resulted in the damped Kawahara equation.The effects of the magnetic field,Landau quantization,the ratio of positron density to electron density,the ratio of positron density to ion density,and the direction cosine on linear dispersion laws as well as soliton and conoidal solutions of the damped Kawahara equation are explored.The understanding from this research can contribute to the broader field of astrophysics and aid in the interpretation of observational data from white dwarfs.