Steady magnetic field generation due to transient field ionization in ultrashort laser-solid interaction

Using particle-in-cell simulations we show that a steady, megagauss magnetic field can be generated due to ionization dephasing in the interaction of an ultrashort laser pulse with a dielectric target. The magnetic field amplitude is limited by the screening of the laser-produced plasma and depends upon the ionization threshold of the target material rather than the laser intensity.