First measurements of radar coherent scatter by the Radio Aurora Explorer CubeSat

• Published in: Geophysical research letters Vol. 39; no. 14
• Main Authors: Bahcivan, H., Cutler, J. W., Bennett, M., Kempke, B., Springmann, J. C., Buonocore, J., Nicolls, M., Doe, R.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 28.07.2012; American Geophysical Union
• Subjects: CubeSat; Earth sciences; Earth, ocean, space; Exact sciences and technology; ionospheric irregularities; PFISR; RAX; United States; Europe; Arctic region; Southern Europe; Italy; polar regions; Alaska; Marches Italy; experimental studies; altitude; Field aligned irregularity; americium; Electrostatic wave; North America; Coherent scattering; Buneman Farley instability; phase velocity; electrical field; saturation; Aurorae; Ion drift; Correlation analysis; Ionization; Radar observation; Incoherent scattering; Polar region; electron density; Excitation; radar methods; Radar echo; storms
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2012GL052249

The Radio Aurora Explorer CubeSat detected the first radar echoes during the solar storm of March 8, 2012. The 300 s ground‐to‐space bi‐static radar experiment was conducted in conjunction with the Poker Flat Incoherent Scatter Radar in the local morning (∼8 am) over Poker Flat, Alaska. The geomagnetic conditions for theEregion field‐aligned irregularity generation were optimal due to strong (about 1500 m/s)F region ion drifts and sufficient E region ionization (electron densities were ∼2 × 1011 m−3). The corresponding Eregion electric field of ∼80 mV/m was larger than the excitation threshold for the Farley‐Buneman instability. An auto‐correlation analysis resolved, for the first time, the distribution of auroralEregion backscatter with 3 km resolution in altitude and sub‐degree resolution in aspect angle. Moreover, the measured Doppler velocities of the UHF scatter shows the phase speed saturation of the meter‐scale plasma waves. The measured Doppler velocity is in excellent agreement with theCs cos θ formula for auroral E region irregularities. Key Points RAX successfull detects coherent scatter RAX resolves FAI in altitude and aspect angle First coherent scatter measurements by a nanosatellite