Analysis of Plasma Irregularities on a Range of Scintillation‐Scales Using the Resolute Bay Incoherent Scatter Radars. Issue 3 (7th March 2020)

• Record Type: Journal Article
• Authors: Lamarche, Leslie J.; Varney, Roger H.; Siefring, Carl L.
• Is Part Of: Journal of geophysical research. Volume 125:Issue 3(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-07
• Subjects: Polar Cap Ionosphere -- Plasma Irregularies -- Gradient Drift Instability -- Polar Patch; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA027112
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Scintillation in the polar cap ionosphere is observed with a Coherent Electromagnetic Radio Tomography (CERTO) receiver while the Resolute Bay Incoherent Scatter Radars (RISR) provide background plasma conditions in a 3D volume. We interpret fluctuations in the very high frequency (VHF) and ultrahigh frequency (UHF) signal associated with mid‐scale ionospheric structuring using 3D density gradients and plasma drift velocity vectors and calculate the maximum gradient drift instability growth rate. Plasma structuring is evident for any plasma density gradient, but sub‐kilometer structures are less likely on the leading edge of polar patches, possibly due to a much faster diffusion rate for small‐scale structures. Structures are much more uniformly distributed around density enhancements that do not have clear leading and trailing edges. Although the gradient drift instability is an important factor in polar cap structuring, linear growth rates are most successful at predicting structuring around isolated density enhancements in consistent plasma flows. For more general density gradients, the time history of a plasma parcel and local diffusion rates must also be considered. Key Points: Plasma structuring can be observed throughout polar cap patches Isolated polar patches may have smaller scale plasma structuring on their trailing edge than leading edge Plasma structuring around general density gradients tends to be uniform and does not necessarily follow the predictions of linear GDI