What is the primary resistance mechanism generated by magnetic fields threaded through interstellar clouds?

Answer

Magnetic pressure, which scales rapidly due to the increase in field strength upon compression.

Magnetic field strength increases dramatically as the cloud contracts (scaling inversely with volume). Since magnetic pressure is proportional to the square of the field strength ($B^2$), the resistance escalates very quickly.

What is the primary resistance mechanism generated by magnetic fields threaded through interstellar clouds?
gravitystar formationpressurecollapseinterstellar cloud