Robert Duncan, Strong Magnetic Fields:
Many fascinating physical effects occur in magnetic fields with strength exceeding the “quantum electrodynamic field strength” of BQ=4.4×1013 Gauss. (This field-strength given by a combination of fundamental constants: BQ = me2c3/he, where me is the mass of the electron, c is the speed of light, h is Planck’s constant divided by 2 π, and e is the charge on an electron.) In fields stronger than BQ, electrons gyrate at nearly the speed of light around magnetic field lines, even in their lowest quantum energy states. Consequently, the ultra-magnetized vacuum — which, according to quantum mechanics, seethes with virtual electron-positron pairs and other particles — becomes birefringent like a calcite crystal, capable of distorting and magnifying images (“magnetic lensing”). X-ray photons traveling through such strong fields readily split into two, or merge together; and many other novel physical effects come into play.