The
Search and Discovery story about hypermagnetized neutron stars (PHYSICS TODAY, May 2005, page 19) says that 1016 G is the strongest magnetic field found anywhere in nature or in the
laboratory. The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory now
produces magnetic fields of 8 × 1018
G. RHIC creates collisions between two 100-GeV beams of gold ions. The magnetic field midway between
two gold nuclei that are passing at a distance of 20 fm so that there are no nuclear interactions is
8 × 1018
G. Within two years the Large Hadron Collider at CERN will smash lead ions together with a total energy
of 1000 TeV. The magnetic field there will be 2 × 1020
G. The volume of these magnetic fields is small compared to that in a star, but it is still large enough
for elementary-particle studies. As pointed out in the story, the large fields are interesting
because they are greater than 4 × 1013
G, the critical quantum-electrodynamic field strength at which the vacuum becomes strongly birefringent
and displays a number of interesting effects involving photons and electrons.
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