Profile reconstruction methods for pulse reflectometry

We present an analysis of the time delay methods of plasma profile reconstr uction applied to ultra-short pulse (USP) reflectometry. As the instantaneo us frequencies become poorly localized in the time domain, even the advance d time-frequency analysis fails to produce reliable values of the time dela y for corresponding modes. Based on the results of analytical modeling of U SP propagation in plasma the signal record analysis method of profile recon struction is proposed. The method has an advantage of relying on a row sign al record rather than on the delay time of each frequency mode, which makes it more robust and reliable for the problem of density profile measurement s using USP reflectometry.