DSpace-CRIS

The Vorticity Experiment (VortEx) sounding rocket mission consisted of two campaigns from Andøya Space Center, with the science objective of correlating vorticity in both horizontal and vertical motions in the lower thermosphere‐mesosphere region, near the terrestrial turbopause. The first campaign (VortEx‐1) took place on 23 March 2023 while the second campaign (VortEx‐2) was conducted on 10 November 2024. The launch for each campaign consisted of an instrumented Terrier Improved Orion rocket aimed at measuring the plasma and neutral characteristics of the lower thermosphere along with another Black Brant IX rocket to disperse chemical tracer trails and obtain neutral wind in the lower thermosphere. In this paper, we primarily focus on the nighttime irregularities observed by the Langmuir probes on VortEx‐1 and VortEx‐2 in the vicinity of plasma enhancements in the E‐region during disturbed geomagnetic conditions. Electric field measurements along with plasma density spectrograms from the VortEx‐2 instrumented payload indicate that the two‐stream instability was likely the mechanism that produced the smaller‐scale features over tens of meters scales associated with a moderate electric field of 24 mV/m in the southwest direction during upleg, but the instabilities were not prominent during downleg when the electric field magnitude is lower. The two‐stream instability is also the likely mechanism for the irregularities observed with VortEx‐1. A zonal wind shear and an associated Sporadic‐E layer were observed during VortEx‐1 from the rocket and EISCAT measurements. The observations indicate dynamic changes in the high‐latitude ionosphere across spatial and temporal differences.

It has been hypothesized that Meteor Radio Afterglows (MRAs) occur due to resonant transition radiation (RTR) where suprathermal electrons emit as they pass through electron density inhomogeneities in a turbulent plasma. Meteor trails are thought to produce suprathermal electrons through anion oxidation, which can be identified through meteor persistent trains. Meteor plasma turbulence can be identified through a non‐specular echo from a meteor radar. We present the first radar observations of a MRA that was also observed to produce a non‐specular echo and a persistent train, which indicate the presence of both plasma turbulence and anion oxidation. The observations were made using the Long Wavelength Array station at Sevilleta (LWA‐SV) and the Spread spectrum Interferometric Multi‐static Meteor radar Observing Network in New Mexico (SIMONe‐NM), the Widefield Persistent Train Camera version 2 (WiPT2) and the Global Meteor Network (GMN). Analysis reveals that while the MRA was spatially coincident a range‐spread, non‐specular echo, the brightest MRA emission came from a portion of the trail 8 km higher than the brightest radar scatter. We find that changes in the mean free path and collision frequency may be responsible for the higher altitude emission despite weaker plasma turbulence there. We also present evidence from the SIMONe‐NM head echo that the MRA and non‐specular echo were coincident with fragmentation of the meteoroid, which may have some role to play in both phenomena.

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