Coherent electron currents in circular charge transport are of great importance in photoinduced processes, magneto-optics, and reaction dynamics of molecules. We present ultrafast magnetic field generation by circularly polarized attosecond ultraviolet laser pulses in molecular media. Simulations in a one electron molecular model ${\mathrm{H}}_2^{+}$ show that the induced magnetic field exhibits periodic oscillations on attosecond time scales, which depends on the laser pulse and molecular alignment. We attribute it to the coherent electronic currents, arising from resonant coherent excitation between the ground and excited electronic states. The temporal evolution of the generated magnetic fields and the induced electronic currents relies on the molecular orbital superposition in the electron coherence, providing a way for controlling ultrafast magnetic field generation.

• Received 23 June 2018

DOI:https://doi.org/10.1103/PhysRevA.98.043410