Extending the length of the flux tube by λ λ ∗ ∗ gives a new length of L = λ λ ∗ ∗ L 0 while the density of the tube remains the same, ρ ρ 0 , which then results in the magnetic field strength increasing by λ λ ∗ ∗ B 0 . Reducing the length of the tubes results in a decrease of the magnetic field's strength.