High altitude large-scale plasma waves in the equatorial electrojet at twilight

• Autores: Chau Chong Shing, Jorge Luis, Hysell, D. L.
• Formato: artículo
• Fecha de Publicación: 2004
• Institución: Instituto Geofísico del Perú
• Repositorio: IGP-Institucional
• Lenguaje: inglés
• OAI Identifier: oai:repositorio.igp.gob.pe:20.500.12816/1829
• Enlace del recurso: http://hdl.handle.net/20.500.12816/1829; https://doi.org/10.5194/angeo-22-4071-2004
• Nivel de acceso: acceso abierto
• Materia: Ionosphere; Ionospheric irregularities; Equatorial ionosphere; Instruments and techniques; http://purl.org/pe-repo/ocde/ford#1.05.01

Jicamarca radar observations of a new class of large-scale plasma waves in the equatorial electrojet (EEJ) are presented and characterized. The study is based on long-term (204 days), single-baseline interferometry observations made in 2003 using a low-power radar mode, also known as JULIA mode, along with a few hours of observations made in an aperture synthesis imaging mode. The large-scale waves are found to occur at high altitudes in the E-region, mainly between 120 and 140km, around twilight (between 18:30 and 20:00 LT), with durations of a few minutes to an hour. In our long-term observations, these large-scale waves occur very often (between 1 and 5 out 10 nights), drift westward (~70 ms–1), exhibit very narrow spectral widths, and have both positive and negative Doppler shifts. The imaging results show that the large-scale waves occur along tilted bands that sweep westward and downward (~30–60ms–1), with a horizontal separation between bands of about 10–15km. The cause of the waves remains unknown.