“…$$ where the unknowns
, and
in system () represent the charge density, the proper mass‐energy density, and the velocity of an electro‐fluid, respectively.
is the speed of light;
is the electrostatic potential in the inertial frame;
is the pressure which satisfies
, where
is the adiabatic index [
5]. In addition,
and
satisfy
, where
is the special internal energy [
5].…”