1 µs broadband frequency sweeping reflectometry for plasma density and fluctuation profile measurements
Abstract
Frequency swept reflectometry has reached the symbolic value of 1 µs sweeping time, this
performance has been made possible due to an improved control of the ramp voltage driving
the frequency source. In parallel, the memory depth of the 1 Gs/s acquisition system has been
upgraded and can provide up to 200 000 density profiles during a plasma discharge.
Additionally, improvements regarding the trigger delay determination for the acquisition, which
needs to be precisely set and the frequency sweep linearity required by this ultra-fast technique
along with the stability of the ramp voltage driving the VCOs, have been made. While this
diagnostic is traditionally dedicated to the density profile measurement, such a fast sweeping
rate can provide the study of fast plasma events and turbulence with unprecedented time and
radial resolution from the edge to the core and thus compete with the fixed frequency systems.
Experimental results obtained on ASDEX Upgrade plasmas will be presented to demonstrate
the performances of the diagnostic.
Domains
Physics [physics]
Origin : Files produced by the author(s)