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A retrospective study of the asymmetry in the ionosphere during the solstices is made using the different geospace parameters in the North and South magnetic hemispheres. Data of total electron content (TEC) and global electron content (GEC) produced from global ionospheric maps, GIM-TEC for 1999–2013, the ionospheric electron content (IEC) measured by TOPEX-Jason 1 and 2 satellites for 2001–2012, the F2 layer critical frequency and peak height measured on board ISIS 1, ISIS 2, and IK19 satellites during 1969–1982, and the earthquakes M5+ occurrences for 1999–2013 are analyzed. Annual asymmetry is observed with GEC and IEC for the years of observation with asymmetry index, AI, showing January > July excess from 0.02 to 0.25. The coincident pattern of January-to-July asymmetry ratio of TEC and IEC colocated along the magnetic longitude sector of 270° ± 5°E in the Pacific Ocean is obtained varying with local time and magnetic latitude. The sea/land differences in the F2 layer peak electron density, NmF2, and the peak height, hmF2, gathered with topside sounding data exhibit tilted ionosphere along the seashores with denser electron population at greater peak heights over the sea. The topside peak electron density NmF2, TEC, IEC, and the hemisphere part of GEC are dominant in the South hemisphere which resembles the pattern for seismic activity with dominant earthquake occurrence in the South magnetic hemisphere. Though the study is made for the hemispheric and annual asymmetry during solstices in the ionosphere, the conclusions seem valid for other aspects of seismic-ionospheric associations with tectonic plate boundaries representing zones of enhanced risk for space weather.

Dynamics of the dayside magnetosphere and proton radiation belt was analyzed during unusual magnetic storm on 21 January 2005. We have found that during the storm from 1712 to 2400 UT, the subsolar magnetopause was continuously located inside geosynchronous orbit due to strong compression. The compression was found to be extremely strong from 1846 to 2035 UT when the dense plasma of fast erupting filament produced the solar wind dynamic pressure Pd peaked up to >100 nPa and, in the first time, the upstream solar wind was observed at geosynchronous orbit during almost 2 hours. Under the extreme compression, the outer magnetosphere at L > 5 was pushed inward and the outer radiation belt particles with energies of several tens of keV moved earthward, became adiabatically accelerated and accumulated in the inner magnetosphere at L 20%, which is well appropriate for erupting filaments and which is in agreement with the upper 27% threshold for the He/H ratio obtained from Cluster measurements.

[1] Detailed tracing of an exhaust plume from a rocket's initial trajectory is a scientifically and diagnostically useful technique. It can provide detailed information on the atmosphere's mean winds, wind shears, turbulent regime, and physical state over a wide altitude range from 50 to 200 km. We analyze Soyuz rocket exhaust plumes from Plesetsk on 21 May 2009 and 27 June 2011, which uncovered significantly different atmospheric states and underlying dynamics. The first case showed highly dynamical conditions in the mesosphere, characterized by vortex structures, wind shears, and small-scale turbulent eddies. The estimated turbulent energy dissipation rates ranged 330–460 mW kg−1. A characteristic balloon-shaped trail was observed at altitudes between 105 and 160 km, having rapid expansion rates of 500–800 m s−1 over the time period of 2 min which can be explained by complex gas dynamic processes in the rocket wake involving the collision of shock waves. In the second case, we show evidence that the rocket exhaust trail persisted without any changes during its motion from Plesetsk via Denmark to the UK for 9 h, indicating extremely stable atmospheric conditions. This case introduces a new state of the summer mesosphere—remarkably quiet conditions, probably never observed before. The rocket plumes studied, related to the initial rocket trajectory, are essentially twilight phenomena as seen from the ground using wideband spectrum cameras, that is, the Sun should be below the horizon by 6°. For the first time, we analyze the dynamics of rocket exhaust products at the initial trajectory in the mesosphere and lower thermosphere using detailed photographic imaging taken from the ground.

Short duration bursts—1–3 s or 0.05–0.15° MLAT—of 32 eV to several hundred eV electrons are regularly observed in the polar rain and mantle precipitation regions by the DMSP satellites. The spacing between bursts is typically 9–12 s (70–90 km) and is sometimes regular but more often irregular. Sometimes quasi-periodic trains of 4 or 5 evenly spaced bursts occur. Electron spectra in the bursts are variable, but typically represent an enhancement of an order of magnitude in the spectral differential energy flux, but without showing signs of field-aligned acceleration. Previous reports of bursty polar cap precipitation consisted of precipitation with large scale (hundreds of km) spatial inhomogeneity of plasma sheet origin under northward IMF conditions. The bursts described herein occur for southward as well as northward IMF Bz, and represent fine structure (7.5 km) within regions that are of magnetosheath origin and which are homogenous over larger spatial scales (>∼100 km). We suggest that the observed phenomena may be related to the nonstationary processes in the outer high latitude magnetosphere.

[1] The global electron content (GEC) derivation is initiated by summing up the total electron content of each cell of Global Positioning System GPS-TEC global map multiplied by the cell area. Algorithm of GEC calculation is improved in the present paper using the electron density varying with height through the total volume of a spherical layer in near-Earth space up to 20,200 km (GPS orbit) reconstructed from TEC with the International Reference Ionosphere model extended to the Plasmasphere (IRI-Plas). An analytical model is first derived for two-phase typical GEC storm profile by a common epoch analysis of 10 storms during 2001–2011 with the starting time put at the origin of the negative phase of GEC departure from the quiet reference (5 day median). It is found that GEC depletion occurs synchronously with decrease of the solar wind velocity and the outset of recovery of the magnetospheric ring current (the equatorial Dst index) and the auroral electrojet (AE index). Thus, the GEC is an indicator of the plasma injection in the ionosphere and plasmasphere with the solar wind energy inducing the positive phase of GEC storm during 24 h with electron number increased by 10–20% followed by a negative phase with GEC decrease by 10–20% during 40 h of a plasma release (ejection) into the magnetosphere tail beyond the three Earth radii (GPS orbit).

[1] We investigate the average properties of geomagnetic storms using the global and local Dxt indices at four Dst stations in 1932–2009. Imposing the condition of complete data availability during storms, our study includes 1268/362/134/59 storms with Dxt minimum less than −50/−100/−150/−200 nT, respectively. The global Dxt minima were, on an average, −94/−156/−216/−275 nT, while deepest storm-time local Dxt minima were −137/−214/−285/−350 nT. Accordingly, the local Dxt minima are typically 25–30% stronger than the global Dxt minima. The distribution of largest storm-time disturbances is strongly peaked at 18 local time (LT), challenging local midnight as the dominant ion source. Relative timing of local minima verifies that stations at earlier LT hour observe their minimum a couple of hours after the deepest minimum, in agreement with westward drift of ions. Storm-time maximum asymmetries were found to increase with storm intensity level from about 70 nT to 150 nT for −50 to −200 nT storms. However, strong storms are relatively more symmetric than weak storms when compared to the typical level of local disturbance. During individual storms the asymmetry can be more than 200 nT. The rate of evolution of storm-time asymmetry is found to be roughly twice as fast for large storms. We emphasize that the unique database of local Dxt indices proves to be very useful in studying the average spatial distribution and temporal evolution of storms.