to a HYPER-I Device Plasma

The ultrashort-pulse reflectometry is considered as a tool for determining the electron density profile in a large magnetic fusion device. We have been developing an ultrashort-pulse reflectometer. This device has higher spatial and temporal resolution than other conventional diagnostics to measure electron density profiles and fluctuations. We have succeeded to obtain the desired range of the millimeter wave from an ultrashort-pulse for a plasma measurement. We have installed the reflectometer on HYPER-I device and operated using a real plasma. In this paper we show the reflectometer configuration and the preliminary experimental results.. Keywords: plasma diagnostics, electron density, microwave, ultrashort-pulse, time-of-fligh