Local currents in magnetic flux tubes and flux ropes Available to Purchase

A magnetic flux tube is a cylindrical region inside which there exists an axial magnetic field that is much larger than the field outside. Magnetic flux tubes exist in nature, for example, in the sun’s photosphere. We show here that magnetic flux tubes can exist as self‐excited dynamos within conducting fluids, in regions where the fluid velocity has a negative radial velocity, in cylindrical coordinates. We find expressions for the local current density, the magnetic force density, the gas pressure, the ohmic power dissipation, the stored magnetic energy, the inductance, and the inherent time constant. A flux rope is a flux tube, plus an axial current and its azimuthal magnetic field. The axial current cannot be generated locally, but it could be injected at one end; that will be the object of another paper.