Monitoring the Equatorial Ionosphere With the Upgraded Unattended Mode at Jicamarca

Abstract

For several years, the Geophysical Institute of Peru (IGP) has monitored the equatorial ionosphere using its main ionospheric radar located at the Jicamarca Radio Observatory. The radar operated in two standard modes: the Incoherent Scatter Radar (ISR) mode, which employs up to 4 High Power Large-Aperture amplifiers with a peak power of 1 MW each and 5% duty cycle, to measure plasma drifts, electron and ion temperatures, and composition, typically operating about 1,000 hr per year; and the Jicamarca Unattended Long-term investigations of the Ionosphere and Atmosphere (JULIA) mode, which used low-power amplifiers (∼20 kW) to study equatorial ionospheric irregularities such as the Equatorial Electrojet, the Equatorial Spread-F, and the 150-km echoes, operating approximately 4,000 hr per year. In 2022, two solid-state transmitters, each with a peak power of 96 kW and duty cycle of 10% were installed to enable unattended ISR measurements, making it possible to combine certain features of the ISR mode and JULIA mode, such as vertical and zonal plasma drifts up to 500 km and the measurements of coherent equatorial echoes like Equatorial Electrojet, 150-km echoes and Equatorial Spread-F. With this new JULIA - Medium Power (JULIA-MP) mode, the observations of equatorial ionospheric parameters have increased to approximately 5,000 hr per year. This paper presents the new JULIA-MP mode, outlining the experimental setup and summarizing the data statistics registered during 2024.