Magnetic field stimulated transitions of excited states in fast mu He+ ions

It is shown that one can stimulate, by using the present-day laboratory mag netic fields, transitions between the lm sub-levels of fast mu He+ ions for med in muon catalyzed fusion. This gives a possibility to drive the populat ion of the lm sub-levels by applying a field of a few Tesla, which affects the reactivation rate and is especially important to the K alpha X-ray prod uction. Strong fields also cause the self-ionization from highly excited st ates of the muonic helium.