### ASA 126th Meeting Denver 1993 October 4-8

## 5aPA1. Dispersive pulse propagation and group velocity.

**Charles E. Bradley
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*Appl. Res. Labs., Univ. of Texas, Austin, TX 78713-8029
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The propagation of pulses in a dissipative medium is investigated both
theoretically and experimentally. The theoretical work is based on the
dissipative dispersion integral, and the measurements are made in an air-filled
periodic waveguide (i.e., the dispersion is Bloch wave dispersion). The
dispersion integral is considered in the context of a sequence of
characteristic pulse duration distances. The pulse propagates without
distortion up to the smallest characteristic distance, and thereafter undergoes
a new variety of distortion as it encounters each subsequent characteristic
distance. Several new solutions of the dispersion integral that exhibit a
variety of novel propagation properties are found. Pulses that shift in
frequency as they propagate, accelerate as they propagate, and propagate at
near-infinite group velocity are found analytically and verified
experimentally. [Work supported by ONR.]