Pulse radar technique for reflectometry on thermonuclear plasmas

A new method to measure density profiles of thermonuclear plasmas with fast pulse radar is proposed. A number of important benefits of pulse radar above the generally used swept frequency reflectometry are given. A test bench experiment at 34 GHz, using pulses with 1.5-ns rise and fall times, showed that a spatial accuracy of about 1 mm can be reached. With ultrafast (200 ps) microwave pulses it is perhaps possible to perform a direct measurement of the density gradient of the plasma from the broadening and the modification of the shape of the reflected pulse.