Can a magnetic field help drain energy from a charged black hole?

Static charged black holes normally lack the ergosphere needed for the Penrose process, but wrapping one in an external magnetic field breaks that symmetry and creates one. Analyzing particle decay at turning points, the authors derive exact efficiency formulas and find specific critical field strengths that either trigger or suppress energy extraction. The result gives a clean, tunable control parameter — magnetic field strength — for how much energy can be pulled from a charged black hole.