  R-modes can generate strong magnetic fields in the core of accreting
millisecond neutron stars (NSs). The diffusion of these fields outside the core
causes the growth of the external magnetic field and thus it affects the
evolution of the spin down rates $\dot{P}$ of the millisecond pulsars (MSPs).
The diffusion of the internal magnetic field provides a new evolutionary path
for the MSPs. This scenario could explain the large $\dot{P}$ of the pulsars
J1823-3021A and J1824-2452A.

High Energy Astrophysical Phenomena