On an electromagnetic calculation of ionospheric conductance that seems to override the field line integrated conductivity.

The ionospheric conductance is the major quantity that determines the interaction of the magnetosphere with the ionosphere, where the magnetosphere is the large region of space affected by Earth's geomagnetic field, and the ionosphere is its electrically conducting inner boundary, lying right on the edge of the atmosphere. Storms and substorms in space dissipate their energy through ionospheric currents, which heat the atmosphere and disrupt satellite orbits. The ionospheric conductance has, heretofore, been estimated using the staticized physics known as electrostatic theory, which finds that it can be computed by integrating the zero-frequency conductivity along the lines of Earth's geomagnetic field.

A Test of Energetic Particle Precipitation Models Using Simultaneous Incoherent Scatter Radar and Van Allen Probes Observations.

Quantification of energetic electron precipitation caused by wave-particle interactions is fundamentally important to understand the cycle of particle energization and loss of the radiation belts. One important way to determine how well the wave-particle interaction models predict losses through pitch-angle scattering into the atmospheric loss cone is the direct comparison between the ionization altitude profiles expected in the atmosphere due to the precipitating fluxes and the ionization profiles actually measured with incoherent scatter radars. This paper reports such a comparison using a forward propagation of loss-cone electron fluxes, calculated with the electron pitch angle diffusion model applied to Van Allen Probes measurements, coupled with the Boulder Electron Radiation to Ionization model, which propagates the fluxes into the atmosphere.

Violation of Hemispheric Symmetry in Integrated Poynting Flux via an Empirical Model.

For southward interplanetary magnetic field (IMF) during local summer, the hemispherically integrated Poynting flux estimated by FAST-satellite-derived empirical models is significantly larger for the northern hemisphere (NH) than for the southern hemisphere (SH). In order to test whether the difference is statistically significant, the model uncertainties have been estimated by dividing the data sets for each hemisphere into two nonintersecting sets, and separately constructing the model using each of the four sets. The model uncertainty appears to be smaller than the estimated asymmetry.

Observations of Reduced Turbulence and Wave Activity in the Arctic Middle Atmosphere Following the January 2015 Sudden Stratospheric Warming.

Measurements of turbulence and waves were made as part of the Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX) on the night of 25-26 January 2015 at Poker Flat Research Range, Chatanika, Alaska (65°N, 147°W). Rocket-borne ionization gauge measurements revealed turbulence in the 70- to 88-km altitude region with energy dissipation rates between 0.1 and 24 mW/kg with an average value of 2.

A previously unrecognized source of the O Atmospheric band emission in Earth's nightglow.

Earth's night sky continuously produces a faint chemiluminescence known as nightglow. Two prominent nighttime emissions around 90 km are the O Atmospheric and the OH Meinel band systems. Despite a plethora of studies since their identification seven decades ago, substantial gaps persist in our understanding of the mechanisms that control them.

Branching Ratios of the N(D) and N(D) Spin-Orbit States Produced in the State-Selected Photodissociation of N Determined Using Time-Sliced Velocity-Mapped-Imaging Photoionization Mass Spectrometry (TS-VMI-PI-MS).

Branching ratios for N(D) and N(D) produced by predissociation of state selected excited nitrogen molecules in the vacuum ultraviolet region have been measured for the first time. The quantum numbers of the excited nitrogen molecule are defined by selective excitation of the nitrogen molecule in the Franck-Condon region from the ground electronic, Σ, vibrational, v″, and rotational, J″ state to an excited E', v', J' state with a tunable vacuum ultraviolet, VUV, laser. The neutral atoms produced by predissociation from this excited state are then selectively ionized with a second tunable VUV laser.

Laboratory Studies of Vibrational Excitation in O( aΔ, v) Involving O, N, and CO.

Collisional removal of electronic energy from O in the low-lying aΔ state is typically an extremely slow process for the v = 0 level. In this study, we report results on the deactivation of O( aΔ, v = 1-3) in collisions with O and CO. Ozone photodissociation in the 200-310 nm Hartley band is the source of O( a, v), and resonance-enhanced multiphoton ionization is used to probe the vibrational-level populations.

New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium.

The question of whether mesospheric OH() rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH() rotational temperatures as a function of vibrational excitation.