  It is shown that in magnetohydrodynamics, the shapes of the magnetic energy
and magnetic helicity spectra can influence whether the magnetic helicity
resistive dissipation time scale is longer, equal to, or shorter than that of
magnetic energy. The calculations highlight that magnetic helicity need not
always dissipate significantly more slowly than magnetic energy. While this may
be implicitly understood in detailed studies of magnetic helicity in plasma
devices, it is not sufficiently emphasized in elementary discussions comparing
magnetic helicity vs. magnetic energy evolution. Measuring magnetic energy and
helicity decay times may provide a posteriori insight into the initial spectra.
