Variational principles for thermostatted systems

A generalized Lagrangian formalism is proposed for dealing with interacting many body systems subject to time reversible friction forces. The corresponding generalized Hamiltonian and Poissonian formalisms are presented. Explicit connection is made between the new Poisson brackets obtained and the 2-forms of conformally symplectic systems recently investigated. Applications to Nose-Hoover and isokinetic dynamics are treated in detail. (C) 1998 American Institute of Physics.