A hypothetical effect of the Maxwell-Proca electromagnetic stresses on galaxy rotation curves

Understand

The Maxwell-Proca electrodynamics corresponding to a finite photon mass causes a substantial change of the Maxwell stress tensor and, under certain circumstances, may cause the electromagnetic stresses to act effectively as "negative pressure." The paper describes a model where this negative pressure imitates gravitational pull and may produce forces comparable to gravity and even become dominant.

• The effect is associated with the random magnetic fields in the galactic disk with a scale exceeding the photon Compton wavelength.
• The presence of a weaker regular field does not affect the forces under consideration.
• The stresses act predominantly on the interstellar gas and cause an additional force pulling the gas towards the center and towards the galactic plane.