Magnetic aspect sensitivity of high‐latitude E region irregularities measured by the RAX‐2 CubeSat

Abstract

The second Radio Aurora Explorer (RAX‐2) satellite has completed more than 30 conjunction experiments with the Advanced Modular Incoherent Scatter Radar chain of incoherent scatter radars in Alaska and Resolute Bay, Canada. Coherent radar echoing occurred during four of the passes: three when E region electron drifts exceeded the ion acoustic speed threshold and one during HF heating of the ionosphere by the High Frequency Active Auroral Research Program heater. In this paper, we present the results for the first three passes associated with backscatter from natural irregularities. We analyze, in detail, the largest drift case because the plasma turbulence was the most intense and because the corresponding ground‐to‐space bistatic scattering geometry was the most favorable for magnetic aspect sensitivity analysis. A set of data analysis procedures including interference removal, autocorrelation analysis, and the application of a radar beam deconvolution algorithm mapped the distribution of E region backscatter with 3 km resolution in altitude and ∼0.1° in magnetic aspect angle. To our knowledge, these are the highest resolution altitude‐resolved magnetic aspect sensitivity measurements made at UHF frequencies in the auroral region. In this paper, we show that despite the large electron drift speed of ∼1500 m/s, the magnetic aspect sensitivity of submeter scale irregularities is much higher than previously reported. The root‐mean‐square of the aspect angle distribution varied monotonically between 0.5° and 0.1° for the altitude range 100–110 km. Findings from this single but compelling event suggest that submeter scale waves propagating at larger angles from the main E×B flow direction (secondary waves) have parallel electric fields that are too small to contribute to E region electron heating. It is possible that anomalous electron heating in the auroral electrojet can be explained by (a) the dynamics of those submeter scale waves propagating in the E×B direction (primary waves) or (b) the dynamics of longer wavelengths.

A theoretical framework for the changing spectral properties of meter‐scale Farley‐Buneman waves between 90 and 125 km altitudes

“…This second term is actually equal to , and it describes the average frictional heating of the electrons in the presence of wave parallel electric fields. In our way of thinking, at their maximum amplitude, the aspect angle could actually be small, which is something that has been reported by Bahcivan et al [], at least for submeter scales. However, after reaching their maximum amplitude, the waves decay through an increase in their aspect angle.…”

New opportunities offered by Cubesats for space research in Latin America: The SUCHAI project case

“…The world is actively working in a number of research areas related to the geosciences (Selva and Krejci, 2012), astronomy, microgravity, space biology and of course space physics (Bahcivan et al, 2014;Jones, 2014). In particular, SPEL is focusing on two topics within space research: microgravity experiments and instrumentation and science for Earth's magnetosphere-ionosphere.…”

AMISR‐14: Observations of equatorial spread F

“…The deployment of AMISR systems at high latitudes has allowed a number of advances in ionospheric studies in the auroral region [e.g., Nishimura et al , ; Lyons et al , ; Akbari et al , ; Bahcivan et al , ]. It is expected that such systems can also greatly help advance our understanding of different ionospheric processes at low latitude and midlatitude.…”