Panels a), c), and e): power spectral densities of the currents to the Langmuir probes at 08:00, 16:24, and 20:46 on 20 January 2015. The red lines show probe 1 and the black lines probe 2. The dashed lines show lower frequency resolution, where data points taken while the RPC-MIP instrument was running have been removed. The error bars show the 95% confidence intervals for the solid curves in blue and the dashed curves in green. Panels b), d), and f) power spectral densities divided by ω².