Long-Lasting Plasma Bubble Over Asia-Pacific Region Triggered by May 2024 Geomagnetic Storm Observed by POD Measurements from Multiple LEO Satellites

This paper presents the detection and characterization of equatorial plasma bubble (EPB) triggered by the May 10-12th, 2024 geomagnetic superstorm and observed using total electron content (TEC) from Spire Global and COSMIC-2 satellite’s precise orbit determination (POD) data. We demonstrate two case studies of TEC depletions associated with this EPB event. The first case was measured by COSMIC-2 E2 satellite which captured a TEC depletion of ~19 TECu in slant TEC (sTEC) over East Australia during 11:00-11:30 UTC on May 11th. The second case was observed by COSMIC-2 E1 satellite which showed sTEC magnitude reduction of ~33 TECu over North Pacific Ocean during 15:30-16:00 UTC on the same day. To obtain an appropriate mapping function for the POD TEC measurements, a simulated model ionosphere using NeQuick G is constructed and several different mapping functions were evaluated. The simulation result indicates that the Foelsche and Kirchengast mapping function with integral ionosphere effective height (IEH) method has ~20% TEC errors for signals with elevation angle at 10° and which is the elevation angle mask used in this study. The converted POD vTEC are compared with vTEC measured by nearby ground-based receivers and cell phones. Comparison results indicate that the topside ionosphere TEC depletion contributes to a ~38% of total TEC depletion measured by ground and phone observations. Amplitude scintillation index (S4) and phase scintillation index (σϕ) of this EPBs event are discussed through POD and RO measurements. The results indicate that the EPBs impacts are dominantly on the signal propagation when the signal pass through altitudes below LEO orbit height.