摘要：This paper is concerned with the symmetry reductions of the ( 3 + 1 ) $(3+ 1)$ -dimensional modified Zakharov–Kuznetsov equation of ion-acoustic waves in a magnetized plasma. The direct symmetry method is applied to determine the symmetry and the corresponding vector field. Then, the considered equation is reduced to lower-dimensional equations with the aid of the obtained symmetry. At last, some exact solutions of the modified Zakharov–Kuznetsov equation are found in terms of the lower-dimensional equations.
关键词：Zakharov–Kuznetsov equation ; Direct symmetry method ; Symmetry reduction
