Research Highlights

The Earth’s upper atmosphere impacts a wide range of technologies, including satellite communication and navigation signals. Specification and forecasting of the upper atmosphere are critical for mitigating these effects. Improved specification of the state of the upper atmosphere can also improve scientific understanding of this region.

In this paper, regression-based deep convolutional neural networks (CNN), with 12 layers, are developed for predicting the maximal amplitude of the southward component of the near-Earth magnetic field from a passing interplanetary coronal mass ejection (ICME).

We conducted numerical simulations to examine dayside thermosphere and ionosphere responses to concurrent solar flares and a geomagnetic storm during September 6th – September 11th, 2017, as well as the interplay of flare and storm effects. We found that E-region electron density response to the flares was much smaller inside the auroral oval than it was outside the auroral oval due to an extra source of ionization by auroral particle precipitation.

We re-examine a 50+ year-old problem of deep central reversals predicted for strong solar spectral lines, in contrast to the smaller reversals seen in observations.

In the context of the solar atmosphere, we re-examine the role of of neutral and ionized species in dissipating the ordered energy of intermediate-mode MHD waves into heat. We solve conservation equations for the hydrodynamics and for hydrogen and helium ionization stages, along closed bundles of magnetic field.

Over the past two decades mounting evidence demonstrated that terrestrial weather significantly influences the dynamics and mean state of the thermosphere. While important progress has been made in understanding how this coupling occurs on hourly to daily time scales, large uncertainty still exists on this effect around intraseasonal (∼30–90 days) time scales.

Evidence of the existence of hydrodynamic and MHD Rossby waves in the Sun is accumulating rapidly. We employ an MHD Rossby wave model for the Sun in simplified Cartesian geometry, with a uniform toroidal field and no differential rotation, to analyze the role of each force that contributes to Rossby wave dynamics, and compute fluid particle trajectories followed in these waves.

We report the first results of a global ionosphere/thermosphere simulation study that self-consistently generates large-scale equatorial spread F (ESF) plasma bubbles in the post-sunset ionosphere. The coupled model comprises the ionospheric code SAMI3 and the atmosphere/thermosphere code WACCM-X.

Philip Judge states that the interpretation of emission lines formed in large astrophysical plasmas such as the solar atmosphere faces many challenges. Relatively simple line-ratio estimates of physical parameters, while appealing, are heavily laden with assumptions.