Reflection of electromagnetic radiation from underdense ionization fronts

摘要

The reflection of radiation pulse from oncoming ionization fronts is studied using two approaches, the resulting reflection coefficient is well above the previous prediction. We show that upon reflection from an ionization front with optimum density, the upshifted frequency of radiation pulse can exceed twice the drive frequency and the reflected energy exceed the incident energy. The extra energy required for pulse amplification can be supplied by the ionizing driver.