A method for pumping production fluid from a wellbore includes deploying a downhole assembly of an artificial lift system (ALS) into the wellbore. The downhole assembly includes a linear electric motor (LEM) and a pump. The method further includes operating the LEM, thereby reciprocating the pump and lifting production fluid from the wellbore to surface. The LEM includes a stator and a reciprocating head having permanent magnets. The production fluid leaks through an interface formed between the head and the stator.