Microwave Interactions with Intense Laser Produced Air-Plasmas

摘要

Ongoing NRL experiments have revealed long-lived (~20 microseconds), efficient microwave reflection from a laser generated plasma region in air. This phenomenon is distinct from the short-lived response (~10ns) typical for laser produced air plasma filaments and represents a thousand-fold increase in the duration of the influence of the plasma region. We believe that the cause of the long-lived reflection is a high-temperature, low-density cavitation region created from dynamic expansion of the laser plasma region. The reduced recombination times in this region allow a sufficiently high plasma density (>10^13 cm