부산대학교 도서관

The ionization-assisted self-compression of a high-power microwave pulse (~250 MW, ~0.5 ns, 9.6 GHz) super-luminal propagation in a gas-filled waveguide is demonstrated experimentally for the first time. Fast increasing of the plasma density within the pulse frame leads to up conversion of the pulse's local frequency. As a result, the wave group velocity increases along the pulse, from the leading front to the tail. The latter leads pulse compression, power enhancement, and propagation with faster velocity than in the empty waveguide. These experimental observations have been confirmed by a one-dimensional theoretical model and three-dimensional particle-in-cell simulations.