Research Highlights

Research Highlights

A selection of highlights culled from publications by HAO staff.

Atomic structure calculations of Land ́e g factors of astrophysical interest with direct applications for solar coronal magnetometry

We perform a detailed theoretical study of the atomic structure of ions with ns2npm ground configurations and focus on departures from LS coupling which directly affect the Land ́e g factors of magnetic dipole lines between levels of the ground terms.

Investigation of a neutral ‘tongue’ observed by GOLD during the geomagnetic storm on May 11,2019

The National Aeronautics and Space Administration Global-scale observations of the Limb and Disk (GOLD) mission observed a unique structure of thermospheric column density ratio of O to N2 (∑O/N2) during a geomagnetic storm on day of year (DOY) 130 (May 10) to DOY 132 in 2019. The percentage difference of ∑O/N2 between the storm time (DOY 131) and the quiet time (DOY 128) had a relatively enhanced ∑O/N2 region sandwiched by two depleted regions over North America and the Atlantic Ocean in the Northern Hemisphere.

A smoothed UV spectrum of α alpha Cen A, obtained by the Hubble Space Telescope

Measuring the magnetic origins of solar flares, CMEs and Space Weather

We take a broad look at the problem of identifying the magnetic solar causes of space weather. The challenges are best met through a combination of near UV lines of bright Mg II, and lines of Fe II and Fe I (mostly within the 4s − 4p transition array) which form in the chromosphere up to 20,000 K.

Scatterplots of hourly mean zonal and meridional wind components at OI layer

A comparison of Fabry-Perot interferometer and meteor radar wind measurements near the polar mesopause region

The neutral winds in the Mesosphere and Lower Thermosphere (MLT) region have been observed at King Sejong Station, Antarctica using a meteor radar and a Fabry-Perot interferometer (FPI) simultaneously. These two independent MLT wind measurements are compared to each other to identify the characteristics of FPI measurement.

Amplitude spectra of ground magnetic northward magnetic perturbation

Ultra-Fast Kelvin Wave (UFKW) Variations in the Surface Magnetic Field

Kelvin waves are large scale wave that is important for Earth’s atmosphere. The Ultra-Fast Kelvin waves (UFKW) are a subset of the Kelvin waves that can propagate to the mesosphere and lower thermosphere (MLT) ~100km and above due to their high zonal phase speeds. 

Edge-enhanced images from near the core of the Mg II k line

Magnetic structure of the solar chromosphere-corona transition regions

The bulk of the emission from the plasma called "transition region" plasma originates from structures energetically connected both to the chromosphere and corona. This result resolves decades of debate and opens the door to measuring magnetic energy and its evolution in the corona using transition region emission lines.

scattering geometry of point P is shown in the observer's frame with projections of the magnetic field components in this frame

On single-point inversions of magnetic dipole lines in the corona

Prompted by a recent paper by Dima and Schad, we re-consider the problem of inferring magnetic properties of the corona using polarimetric observations of magnetic dipole (M1) lines.

Three panels display the active-regions' toroid patterns

Deciphering Deep-Origin of Active Regions From Analysis Of Magnetograms

Dikpati, et. al., derive magnetic toroids from surface magnetograms by employing a novel optimization method based on Trust Region Reflective algorithm. 

Root-Mean-Square Difference of the plasma drift between C/NOFS data and FORMOSAT-3/COSMIC DART/TIE-GCM ensemble data assimilation computed separately for the four geomagnetic longitudinal sectors

Data-Driven Ensemble Modeling of Equatorial Ionospheric Electrodynamics

A Case Study During a Minor Storm Period Under Solar Minimum Conditions: The dayside equatorial ionospheric electrodynamics exhibits strong variability driven simultaneously by highly changeable external forcings that originate from the Sun, magnetosphere, and lower atmosphere.