Dissipation flow-frames: particle, energy, thermometer

Understand

We associate the following physical co-mover conditions of to different frame choices: i) Eckart: particle flow, ii) Landau-Lifshitz: energy flow, iii) J\"uttner: moving thermometer frame.

• The role of fixing a flow-frame is analysed with respect to local equilibrium concentrating on dissipative currents and forces in single component relativistic fluids.
• The special role of a "J\"uttner frame" is explored and contrasted to the more common Eckart and Landau-Lifshitz choices.