  A simple one-dimensional gas-piston kinetic model gives the interaction
potential between two colliding heavy ions. In the frame of the classical,
thermodynamical approach, the colliding heavy ions are not submitted to
friction, but produces an irreversible phenomena with cause at the difference
of pressure $p$ "felt" by the nucleon gas when ions collide with the target
when compared with the pressure that nuclear matter exert on their boundaries
when in thermodynamical equilibrium, and offers a straightforward way to
calculate interacting potentials.
