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Abstract. Previous efforts have used pairs of closely spaced specialized receivers to measure Global Navigation Satellite System (GNSS) signals and to estimate ionospheric irregularity drifts. The relatively high cost associated with commercial GNSS-based ionospheric receivers has somewhat limited their deployment and the estimation of ionospheric drifts. The development of an alternative, low-cost, GNSS-based scintillation monitor (ScintPi) motivated us to investigate the possibility of using it to overcome this limitation. ScintPi monitors can observe signals from geostationary satellites, which can greatly simplify the estimation of the drifts. We present the results of an experiment to evaluate the use of ScintPi 3.0 to estimate ionospheric irregularity drifts. The experiment consisted of two ScintPi 3.0 deployed in Campina Grande, Brazil (7.213° S, 35.907° W; dip latitude ∼ 14° S). The monitors were spaced at a distance of 140 m in the magnetic east–west direction and targeted the estimation of the zonal drifts associated with scintillation-causing equatorial spread F (ESF) irregularities. Routine observations throughout an entire ESF season (September 2022–April 2023) were made as part of the experiment. We focused on the results of irregularity drifts derived from geostationary satellite signals. The results show that the local time variation in the estimated irregularity zonal drifts is in good agreement with previous measurements and with the expected behavior of the background zonal plasma drifts. Our results also reveal a seasonal trend in the irregularity zonal drifts. The trend follows the seasonal behavior of the zonal component of the thermospheric neutral winds as predicted by the Horizontal Wind Model (HMW14). This is explained by the fact that low-latitude ionospheric F-region plasma drifts are controlled, in great part, by Pedersen-conductivity-weighted flux-tube-integrated zonal neutral winds. The results confirm that ScintPi has the potential to contribute to new, cost-effective measurements of ionospheric irregularity drifts, in addition to scintillation and total electron content. Furthermore, the results indicate that these new ScintPi measurements can provide insight into ionosphere–thermosphere coupling.
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On the Role of Mild Substorms and Enhanced Hall Conductivity in the Plasma Irregularities Onset and Zonal Drift Reversals: Experimental Evidence at Distinct Longitudes Over South America
Abstract The 14‐panel Advanced Modular Incoherent Scatter Radar (AMISR‐14) system deployed at Jicamarca observed equatorial spread F plumes on two consecutive nights under unfavorable seasonal and solar flux conditions during a period that can be categorized as geomagnetically quiet. The AMISR‐14 capability of observing in multiple pointing directions allowed the characterization of the irregularity zonal drifts revealing that, in addition to their atypical occurrence, the zonal drifts of these plumes/irregularities also presented distinct patterns from one night to another, reversing from east to west on the second night. This work addresses two main subjects: (a) the mechanisms that may have led to the generation of these irregularities, despite the unfavorable conditions, and (b) the mechanisms that possibly led to the reversal (east‐to‐west) in the zonal plasma drift on the second night. To do so a multi‐instrumented and multi‐location investigation was performed. The results indicate the occurrence of simultaneous spread‐F events over the Peruvian and the Brazilian regions, evidencing a non‐local process favoring the development of the irregularities. The results also suggest that, even under very mild geomagnetic perturbation conditions, the recurring penetration of electric fields in the equatorial ionosphere can occur promptly, modifying the equatorial electrodynamics and providing favorable conditions for the plume development. Moreover, the results confirm that the eastward penetration electric fields, combined with the upsurge of Hall conductivity in the nighttime typically associated with the presence of sporadic‐E layers, are likely to be the mechanism leading to the reversal in the irregularity zonal drifts over these regions.
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- PAR ID:
- 10477525
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Earth and Space Science
- Volume:
- 10
- Issue:
- 11
- ISSN:
- 2333-5084
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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