A modified Li-He’s variational principle for plasma

Purpose It is extremely difficult to establish a variational principle for plasma. Kalaawy obtained a variational principle by using the semi-inverse method in 2016, and Li and He suggested a modification in 2017. This paper aims to search for a generalized variational formulation with a free parameter. Design/methodology/approach The semi-inverse method is used by suitable construction of a trial functional with some free parameters. Findings A modification of Li-He’s variational principle with a free parameter is obtained. Originality/value This paper suggests a new approach to construction of a trial-functional with some free parameters.