Critical nucleus charge in a superstrong magnetic field

Due to strong enhancement of loop effects in a superstrong magnetic field (B m²/e³) the Coulomb potential becomes screened. This phenomenon dramatically changes the dependence of the electron energy levels on magnetic field. In particular, the freezing of energy levels occurs so the ground energy level of light ions can never reach the lower continuum (become critical), no matter how strong the field is. Therefore, the magnetic field affects the critical nucleus charge Z_cr in two ways: i. it makes the electron movement essentially one-dimensional diminishing the value of Z_cr; ii. it makes the potential weaker increasing the value of critical charge. The phenomenon of critical charge itself is also discussed.