Correlation of in situ measurements of plasma irregularities with ground-based scintillation observations

We present here the first comparison of in situ ion density fluctuations measured by the Planar Langmuir Probe on Communication\Navigation Outage Forecasting System (C/NOFS) with coincident ground‐based measurements of scintillation from the Scintillation Decision Aid (SCINDA) network and coherent scatter radar located on Christmas Island (3°N, 157°W) over a 15 month period from May 2008 through June 2009. The Planar Langmuir Probe on C/NOFS measures absolute ion densities from 10 to 108 cm−3 at a rate up to 1024 Hz. The instrument is conceptually similar to ion traps and retarding potential analyzers that have flown on many past satellite and rocket missions. However, the present design includes advances in electronic capability compared with past designs. Initial results from this study show that in situ density fluctuations observed on magnetic flux tubes that pass over Christmas Island can be used as an indicator of ionospheric radio wave scintillation at that site. This is true even when the measurements are made at horizontal ranges of over 1000 km away from the ground site as long as the field line apex altitudes are less than ∼600 km.