Lie Group analysis of Plasma equilibrium equations
  In this paper we perform Lie group analysis of systems of partial differential equations which describe different cases of classical plasma equilibria, and find groups of transformations admitted by those equations in several important cases.   We also give a recipe how to apply Lie formalism to look for B\"{a}cklund transformations between systems of partial differential equations, using plasma equilibrium system as an example. 
Alexei F. Cheviakov