[pfdietz]

Both meanings were used here. There are electrical currents, and there are flows of material through the magnetic field, producing voltages that sustain currents. The JxB forces also affect the flows. It's a highly nonlinear phenomenon (magnetohydronamics, or MHD).

[pfdietz]

Magnetohydrodynamics (spelling)

[defrost]

Magnetotellurics (cool geophysical passive imaging technique)

[pfdietz]

That's a bit different; it doesn't have the feedback where the JxB force pushes matter around, altering the flow.