Nearly simultaneous measurements of radar auroral heights and Doppler velocities at 398 MHz

Journal Article · Wed Apr 01 04:00:00 EST 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA04p03333· OSTI ID:5510535

Moorcroft, D; Ruohoniemi, J M ^[1]

---

1. Univ. of Western Ontario, London (Canada)

Nearly simultaneous measurements of radar auroral heights and Doppler velocities were obtained using the Homer, Alaska, 398-MHz phased-array radar over a total of 16 hours on four different days. The heights show a consistent variation with time, being highest near the time of electrojet current reversal, and lowest late in the morning. A variety of east-west height asymmetries were observed, different from those previously reported, which can be explained in terms of favorable flow angles preferentially favoring high-altitude primary two-stream waves to one side of the field of view. Low-velocity echoes, presumably due to secondary irregularities, are found to be more restricted in height range than echoes with ion acoustic velocities, which presumably come from primary two-stream instabilities. Echo power was examined as a function of velocity and height. For the westward electrojet it was found that echoes with ion acoustic velocities are relatively constant in strength over most of their height range, but for low-velocity echoes the power is a maximum between 100 and 105 km and falls off steadily at greater heights. Doppler speeds show a noticeable decrease at heights below 105 km, in agreement with the expected variation in ion acoustic velocity.

• OSTI ID: 5510535
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 92:A4; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
AURORAL ZONES
BACKSCATTERING
CURRENTS
DIMENSIONS
DOPPLER EFFECT
E REGION
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTROJETS
HEIGHT
IONOSPHERE
MEASURING INSTRUMENTS
PLANETARY IONOSPHERES
PLASMA WAVES
RADAR
RANGE FINDERS
SCATTERING
VARIATIONS
VELOCITY
VIRTUAL HEIGHT