Simulations of a pulsed direct current discharge are performed for a 7% argon in helium mixture at a pressure of 270 Torr using both zero- and one-dimensional models. Kinetics of species relevant to the operation of an optically pumped rare-gas laser are analyzed throughout the pulse duration to identify key reaction pathways. Time dependent densities, electron temperatures, current densities, and reduced electric fields in the positive column are analyzed over a single 20 μs pulse, showing temporal agreement between the two models. Through the use of a robust reaction rate package, radiation trapping is determined to play a key role in reducing $Ar(1s_5)$ metastable loss rates through the reaction sequence $Ar(1s_5)+e^{-}\to Ar(1s_4)+e^{-}$ followed by $Ar(1s_4)\to Ar+\hslash \omega$ . Collisions with He are observed to be responsible for $Ar(2p_9)$ mixing, with nearly equal rates to $Ar(2p_{10})$ and $Ar(2p_8)$ . Additionally, dissociative recombination of $A{r}_2^{+}$ is determined to be the dominant electron loss mechanism for the simulated discharge conditions and cavity size.

Simulations of an α-mode radio frequency dielectric barrier discharge are performed for varying mixtures of argon and helium at pressures ranging from 200 to 500 Torr using both zero and one-dimensional models. Metastable densities are analyzed as a function of argon-helium mixture and pressure to determine the optimal conditions, maximizing metastable density for use in an optically pumped rare gas laser. Argon fractions corresponding to the peak metastable densities are found to be pressure dependent, shifting from approximately 15% Ar in He at 200 Torr to 10% at 500 Torr. A decrease in metastable density is observed as pressure is increased due to a diminution in the reduced electric field and a quadratic increase in metastable loss rates through $A{r}_2^{*}$ formation. A zero-dimensional effective direct current model of the dielectric barrier discharge is implemented, showing agreement with the trends predicted by the one-dimensional fluid model in the bulk plasma.

The combination of the Wang‐Sheeley‐Arge (WSA) coronal model, ENLIL heliospherical model version 2.7, and CONED Model version 1.3 (WSA‐ENLIL with CONED Model) was employed to form ensemble forecasts for 15 halo coronal mass ejections (halo CMEs). The input parameter distributions were formed from 100 sets of CME cone parameters derived from the CONED Model. The CONED Model used image processing along with the bootstrap approach to automatically calculate cone parameter distributions from SOHO/LASCO imagery based on techniques described by Pulkkinen et al. (2010). The input parameter distributions were used as input to WSA‐ENLIL to calculate the temporal evolution of the CMEs, which were analyzed to determine the propagation times to the L₁ Lagrangian point and the maximum K_p indices due to the impact of the CMEs on the Earth's magnetosphere. The Newell et al. (2007) K_p index formula was employed to calculate the maximum K_p indices based on the predicted solar wind parameters near Earth assuming two magnetic field orientations: a completely southward magnetic field and a uniformly distributed clock‐angle in the Newell et al. (2007) K_p index formula. The forecasts for 5 of the 15 events had accuracy such that the actual propagation time was within the ensemble average plus or minus one standard deviation. Using the completely southward magnetic field assumption, 10 of the 15 events contained the actual maximum K_p index within the range of the ensemble forecast, compared to 9 of the 15 events when using a uniformly distributed clock angle.

An updated global climatology of blanketing sporadic E (E_s) is developed from a combined data set of Global Positioning System (GPS) radio occultation (RO) and ground‐based ionosonde soundings over the period of September 2006–January 2019. A total of 46 sites and 3.2 million total soundings from the Global Ionosphere Radio Observatory network in combination with 3.0 million occultations from the Constellation Observing System for Meteorology, Ionosphere, and Climate constellation are used to calculate global occurrence rates (ORs) for two blanketing frequency thresholds: all blanketing sporadic‐E with no limit on intensity (all‐E_s) and moderate‐E_swith fbEs ≥ 3 MHz. Following the GPS‐RO to ionosonde comparison by Carmona et al. (2022),https://doi.org/10.3390/rs14030581the all‐E_srates are calculated using ionosonde data and an amplitude‐based S₄threshold for the GPS‐RO data while the moderate‐E_srates use a primarily phase‐based technique. Occurrence rates are separated by intensity, season, month, and solar local time for quiet geomagnetic conditions. Overall, the general geomagnetic trends agree with previous E_sclimatologies and the ORs peak near 50% for all‐E_sand 25% for moderate‐E_smeasured in the mid‐latitudes during local summer in the late afternoon. Low ORs are observed near the South Atlantic Anomaly and North America, and a general asymmetry is observed between hemispheres with higher ORs in the Northern Hemisphere. High‐latitude and late morning blanketing E_sare found to be stronger but less frequent with rates nearly equal to the moderate‐E_smid‐latitude maximums.

Sporadic-E ($E_s$) occurrence rates from Global Position Satellite radio occultation (GPS-RO) measurements have shown to vary by a factor of five between studies, motivating the need for a comparison with ground-based measurements. In an attempt to find accurate GPS-RO techniques for detecting $E_s$ formation, occurrence rates derived using five previously developed GPS-RO techniques are compared to ionosonde measurements over an eight-year period from 2010–2017. GPS-RO measurements within 170 km of a ionosonde site are used to calculate $E_s$ occurrence rates and compared to the ground-truth ionosonde measurements. The techniques are compared individually for each ionosonde site and then combined to determine the most accurate GPS-RO technique for two thresholds on sporadic-E intensity: no lower limit and fbEs $\ge 3$ MHz. Overall, the Yu$S_4$ method shows the closest agreement with ionosonde measurements for total $E_s$ occurrence rates without a lower limit on intensity, while the phase-based Chu technique shows the closest agreement for fbEs $\ge 3$ MHz. This analysis demonstrates that the variation in GPS-RO derived sporadic-E occurrence rates is due to varying thresholds on the sporadic-E intensities in terms of fbEs.