Super strong magnetic field's effect on radioactivity

[arusse02]

Is it possible that a super strong magnetic field, like those from a magnetar, could increase the instability of a radioactive atom and therefore decrease the half life? Thanks for your response in advance.

 

[mfb]

In general magnetic fields will change the energy levels and therefore the lifetime, especially for alpha decay (but not limited to it). You can even make stable nuclei unstable and vice versa.
What changes how is difficult to tell without a longer analysis.