An atom, molecule or speck of dust placed at the focus of the world's most powerful x-ray laser doesn't stand a chance. The illuminated matter reaches a temperature in excess of one million kelvins, as hot as the solar corona, in less than a trillionth of a second. Atoms of, for example, neon subjected to such extreme radiation rapidly lose all 10 of their electrons, and once they have lost their protective cloak of electrons, they explode away from neighboring atoms. For physicists, the trail of destruction holds a peculiar fascination.
What makes the process astonishing is that the laser boils away the atoms' electrons from the inside out. The electrons, which surround the nucleus of the atom in onionlike orbital shells, do not all react uniformly to the x-ray beam. The outer shells are nearly transparent to x-rays, so the inner shell takes the brunt of the radiation, much as coffee in a microwave oven is heated long before the cup that holds it. The two electrons in that shell shoot off, leaving empty space in their wake; the atom is hollow. Within a few femtoseconds (quadrillionths of a second), other electrons get sucked in to replace the lost ones, and the cycle of core-hole formation and vacancy filling continues until no electrons are left. This process occurs for molecules as well as solid matter.