Magnetic tension force

The magnetic tension force is a restoring force (SI unit: Pa·m⁻¹) that acts to straighten bent magnetic field lines. It equals:

It is analogous to rubber bands and their restoring force. The force is directed antiradially. Although magnetic tension is referred to as a force, it is actually a pressure gradient (Pa m⁻¹) which is also a force density (N m⁻³).

The magnetic pressure is the energy density of the magnetic field which can be visualized as increasing as magnetic field lines converge in a given volume of space. In contrast, magnetic tension force is determined by how much the magnetic pressure changes with distance. Magnetic tension forces also rely on vector current densities ${\displaystyle \mathbf {J} }$ and their interaction with the magnetic field ${\displaystyle \mathbf {B} }$. Plotting magnetic tension along adjacent field lines can give a picture as to their divergence and convergence with respect to each other as well as current densities ${\displaystyle \mathbf {J} }$.

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