We utilize the improved Riccati equation method to construct more general exact solutions to nonlinear equations. And we obtain the travelling wave solutions involving parameters, which are expressed by the hyperbolic functions, the trigonometric functions, and the rational functions. When the parameters are taken as special values, the method provides not only solitary wave solutions but also periodic waves solutions. The method appears to be easier and more convenient by means of a symbolic computation system. Of course, it is also effective to solve other nonlinear evolution equations in mathematical physics.

More and more problems in the branches of modern mathematical physics are described in terms of suitable nonlinear models, and nonlinear physical phenomena are related to nonlinear equations, which are involved in many fields from physics to biology, chemistry, mechanics, and so forth. Nonlinear wave phenomena are very important in nonlinear sciences, in recent years, much effort has been spent on the construction of exact solutions of nonlinear partial differential equations. Many powerful and efficient methods have been presented to obtain the exact traveling wave solutions of nonlinear evolution equations, such as the Backlund transformation method [

The ZK equation governs the behavior of weakly nonlinear ion-acoustic waves in plasma comprising cold ions and hot isothermal electrons in the presence of a uniform magnetic field. When the ion or electron plasma does not meet the Boltzmann distribution, Munro and Parkes derive the modified ZK equation (mZK equation), they also studied planar periodic two-dimensional long-wave perturbation wave solutions and the stability of traveling wave solutions in isolation [

The

The paper is motivated by the desire to present a new method, named the improved Riccati equation method, so that it can be successfully applied to seeking the exact travelling wave solutions to the mZK equation. We will obtion two group values of coefficients regarding Riccati equation and nonlinear evolution equation. By contrast to both Riccati equation method and

We consider the nonlinear evolution equations in three independent variables

We seek their traveling wave solutions in the following form

Equation (

In order to construct travelling wave solutions of nonlinear equations, it is reasonable to introduce the following ansatz

We substitute (

Then we substitute (

We consider the modified Zakharov-Kuznetsov (mZK) equations in the following form:

We also make the transformation

By balancing the highest order derivative terms and nonlinear terms in (

On substituting (

Similarly, we can also get the following result.

Using Case

When

If

If

When

If

If

Using Case

When

If

If

When

When

If

If

In summary, the improved Riccati equation method has been proposed and used to find out exact solutions of nonlinear equations with the aid of Mathmatica software. Our method allows us carry out the solution process of nonlinear wave equations more systematically and conveniently by computer algebra systems such as Maple and Mathematica. We have successfully obtained some travelling wave solutions of the mZK equations. When the parameters are taken as special values, the solitary wave solutions and periodic wave solutions are obtained. We surely believe that these solutions will be of great importance for analyzing the nonlinear phenomena arising in applied physical sciences. The work shows that the improved Riccati equation method is sufficient, effective and suitable for solving other nonlinear evolution equations, it deserves further applying and studying as well.

During the work on this project, the author received invaluable advise and help from a lot of colleagues and friends. In particular, the author would like to thank Jiahua Han and Jiancheng Ji who cooperated with him.