Chris Watson

The geomagnetic storm that started on May 10th 2024, often referred to as the “Mother’s Day” or “Gannon” storm, was the strongest storm for decades,with polar lights visible across significant parts of the globe. This paper focuses on the impacts in the form of GNSS signal scintillation in the Arctic, covering the geographic area from 50 to 85° N and 160° W to 40° E. The scintillation analysis is supported by ionospheric convection data from the Super Dual Auroral Radar Network (SuperDARN) and currents estimated from the measurements of multiple magnetometer arrays. Positioning performance is examined for a real-time kinematic (RTK) service in Tromsø, at ≈70° N. An overview of the spatial and temporal occurrence of the scintillation is presented. Scintillation was observed throughout the coverage area, in connection with the auroral oval region and a tongue of ionization. Amplitude scintillation was observed but with a lesser magnitude (S4 values up to 0.2) and extent than the phase scintillation. The connection of the scintillation to the auroral electrojets and vertical currents is examined in detail. Scintillation is found to occur within both the eastward and westward electrojets, but is not a constant feature. Phase scintillation in the eastward electrojet tends to occur near the poleward boundary. Some periods of strong vertical currents are associated with scintillation. Accurate positioning services were severely degraded during the event. For many users, they would be unusable for up to 37 consecutive hours. To the best of our knowledge, at the time of writing, this paper presents the most complete overview of high-latitude scintillations during this storm, and demonstrates the value of combining data from multiple instruments for enhanced insight.

This work aims to demonstrate that dense networks of low‐cost dual‐frequency global navigation satellite systems (GNSS) receivers can be used to retrieve ionospheric electron content with almost the same level of accuracy as scientific‐grade GNSS receivers. A network of 15 GNSS receivers called EclipseNB was designed and installed in New Brunswick, Canada to study ionospheric structure and dynamic behavior, including the response of the ionosphere to the total solar eclipse in April 2024. EclipseNB observations during the solar eclipse and the extreme geomagnetic storm in May 2024 are presented. The status and the future of the network are discussed.

The high latitude ionospheric evolution of the May 10‐11, 2024, geomagnetic storm is investigated in terms of Total Electron Content and contextualized with Incoherent Scatter Radar and ionosonde observations. Substantial plasma lifting is observed within the initial Storm Enhanced Density plume with ionospheric peak heights increasing by 150–300 km, reaching levels of up to 630 km. Scintillation is observed within the cusp during the initial expansion phase of the storm, spreading across the auroral oval thereafter. Patch transport into the polar cap produces broad regions of scintillation that are rapidly cleared from the region after a strong Interplanetary Magnetic Field reversal at 2230UT. Strong heating and composition changes result in the complete absence of the F2‐layer on the eleventh, suffocating high latitude convection from dense plasma necessary for Tongue of Ionization and patch formation, ultimately resulting in a suppression of polar cap scintillation on the eleventh.

The high latitude ionospheric evolution of the May 10-11, 2024, geomagnetic storm is investigated in terms of Total Electron Content and contextualized with Incoherent Scatter Radar and ionosonde observations. Substantial plasma lifting is observed within the initial Storm Enhanced Density plume with ionospheric peak heights increasing by 150km to 300km, reaching levels of up to 630km. Scintillation is observed within the cusp during the initial expansion phase of the storm, spreading across the auroral oval thereafter. Patch transport into the polar cap produces broad regions of scintillation that are rapidly cleared from the region after a strong Interplanetary Magnetic Field reversal at 2230UT. Strong heating and composition changes result in the complete absence of the F2-layer on the 11th, suffocating high latitude convection from dense plasma necessary for Tongue of Ionization and patch formation, ultimately resulting in a suppression of polar cap scintillation on the 11th.

The lunar ionosphere is a ∼100 km thick layer of electrically charged plasma surrounding the moon. Despite knowledge of its existence for decades, the structure and dynamics of the lunar plasma remain a mystery due to lack of consistent observational capacity. An enhanced observational picture of the lunar ionosphere and improved understanding of its formation/loss mechanisms is critical for understanding the lunar environment as a whole and assessing potential safety and economic hazards associated with lunar exploration and habitation. To address the high priority need for observations of the electrically charged constituents nikear the lunar surface, we introduce a concept study for the Radio Instrument Package for Lunar Ionospheric Observation (RIPLIO). RIPLIO would consist of a multi‐CubeSat constellation (at least two satellites) in lunar orbit for the purpose of conducting “crosslink” radio occultation measurements of the lunar ionosphere, with at least one satellite carrying a very high frequency (VHF) transmitter broadcasting at multiple frequencies, and at least one satellite flying a broadband receiver to monitor transmitting satellites. Radio occultations intermittently occur when satellite‐to‐satellite signals cross through the lunar ionosphere, and the resulting phase perturbations of VikHF signals may be analyzed to infer the ionosphere electron content and high‐ resolution vertical electron density profiles. As demonstrated in this study, RIPLIO would provide a novel means for lunar observation, with the potential to provide long‐term, high‐resolution observations of the lunar ionosphere with unprecedented pan‐lunar detail.

The lunar ionosphere is a ~100 km thick layer of electrically charged plasma surrounding the moon. Despite knowledge of its existence for decades, the structure and dynamics of the lunar plasma remain a mystery due to lack of consistent observational capacity. An enhanced observational picture of the lunar ionosphere and improved understanding of its formation/loss mechanisms is critical for understanding the lunar environment as a whole and assessing potential safety and economic hazards associated with lunar exploration and habitation. To address the high priority need for observations of the electrically charged constituents near the lunar surface, we introduce a concept study for the Radio Instrument Package for Lunar Ionospheric Observation (RIPLIO). RIPLIO would consist of a multi-CubeSat constellation (at least two satellites) in lunar orbit for the purpose of conducting “crosslink” radio occultation measurements of the lunar ionosphere, with at least one satellite carrying a very high frequency (VHF) transmitter broadcasting at multiple frequencies, and at least one satellite flying a broadband receiver to monitor transmitting satellites. Radio occultations intermittently occur when satellite-to-satellite signals cross through the lunar ionosphere, and the resulting phase perturbations of VHF signals may be analyzed to infer the ionosphere electron content and high- resolution vertical electron density profiles. As demonstrated in this study, RIPLIO would provide a novel means for lunar observation, with the potential to provide long-term, high-resolution observations of the lunar ionosphere with unprecedented pan-lunar detail.