The properties of matter are significantly modified by strong magnetic fields , B \gg m _ { e } ^ { 2 } e ^ { 3 } c / \hbar ^ { 3 } = 2.35 \times 10 ^ { 9 } Gauss ( 1 { G } = 10 ^ { -4 } { Tesla } ) , as are typically found on the surfaces of neutron stars . In such strong magnetic fields , the Coulomb force on an electron acts as a small perturbation compared to the magnetic force . The strong field condition can also be mimicked in laboratory semiconductors . Because of the strong magnetic confinement of electrons perpendicular to the field , atoms attain a much greater binding energy compared to the zero-field case , and various other bound states become possible , including molecular chains and three-dimensional condensed matter . This article reviews the electronic structure of atoms , molecules and bulk matter , as well as the thermodynamic properties of dense plasma , in strong magnetic fields , 10 ^ { 9 } { G } \ll B \mathrel { \raise 1.29 pt \hbox { $ < $ } \mkern - 14.0 mu \lower 2.58 pt% \hbox { $ \sim$ } } 10 ^ { 16 } G. The focus is on the basic physical pictures and approximate scaling relations , although various theoretical approaches and numerical results are also discussed . For the neutron star surface composed of light elements such as hydrogen or helium , the outermost layer constitutes a nondegenerate , partially ionized Coulomb plasma if B \ll 10 ^ { 14 } G , and may be in the form of a condensed liquid if the magnetic field is stronger ( and temperature \mathrel { \raise 1.29 pt \hbox { $ < $ } \mkern - 14.0 mu \lower 2.58 pt \hbox { $ \sim$ } } 10 ^ { 6 } K ) . For the iron surface , the outermost layer of the neutron star can be in a gaseous or a condensed phase depending on the cohesive property of the iron condensate .