Improved reflectometer electron density profile measurements on DIII-D

Details are presented of recent improvements to hardware and analysis code components of the DIII-D density profile reflectometer system. The improvements to the hardware increased the system signal-to-noise ratio and reduced spurious reflections. An improved automated method is developed to accurately determine the zero density plasma start position. With these improvements the uncertainty in the zero density plasma start position is reduced from ∼7 to ∼2 mm, the position uncertainty with a fixed mirror target is reduced from ∼4 to ∼2 mm, and the time resolution is improved to 10 μs (previously ∼100 μs).